<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.smartbank.com/role/CommitmentsAndContingentLiabilities" xlink:href="smbk-20190331.xsd#CommitmentsAndContingentLiabilities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/CommitmentsAndContingentLiabilitiesDetails" xlink:href="smbk-20190331.xsd#CommitmentsAndContingentLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/CommitmentsAndContingentLiabilitiesTables" xlink:href="smbk-20190331.xsd#CommitmentsAndContingentLiabilitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedBalanceSheets" xlink:href="smbk-20190331.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="smbk-20190331.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedStatementOfChangesInStockholdersEquity" xlink:href="smbk-20190331.xsd#ConsolidatedStatementOfChangesInStockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="smbk-20190331.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="smbk-20190331.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:href="smbk-20190331.xsd#ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/ConsolidatedStatementsOfIncome" xlink:href="smbk-20190331.xsd#ConsolidatedStatementsOfIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/Derivatives" xlink:href="smbk-20190331.xsd#Derivatives" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DerivativesFairValueHedgesInBalanceSheetDetails" xlink:href="smbk-20190331.xsd#DerivativesFairValueHedgesInBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DerivativesFairValueHedgesOnBalanceSheetDetails" xlink:href="smbk-20190331.xsd#DerivativesFairValueHedgesOnBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DerivativesFairValueHedgesOnIncomeStatementDetails" xlink:href="smbk-20190331.xsd#DerivativesFairValueHedgesOnIncomeStatementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DerivativesNarrativeDetails" xlink:href="smbk-20190331.xsd#DerivativesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DerivativesTables" xlink:href="smbk-20190331.xsd#DerivativesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/DocumentAndEntityInformation" xlink:href="smbk-20190331.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/EarningsPerShare" xlink:href="smbk-20190331.xsd#EarningsPerShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/EarningsPerShareBasicAndDilutedDetails" xlink:href="smbk-20190331.xsd#EarningsPerShareBasicAndDilutedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/EarningsPerShareNarrativeDetails" xlink:href="smbk-20190331.xsd#EarningsPerShareNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/EarningsPerShareTables" xlink:href="smbk-20190331.xsd#EarningsPerShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosures" xlink:href="smbk-20190331.xsd#FairValueDisclosures" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnNonrecurringBasisDetails" xlink:href="smbk-20190331.xsd#FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnNonrecurringBasisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnRecurringBasisDetails" xlink:href="smbk-20190331.xsd#FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnRecurringBasisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosuresCarryingAmountAndEstimatedFairValueOfFinancialInstrumentsDetails" xlink:href="smbk-20190331.xsd#FairValueDisclosuresCarryingAmountAndEstimatedFairValueOfFinancialInstrumentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosuresFairValueDisclosuresUnobservableInputsDetails" xlink:href="smbk-20190331.xsd#FairValueDisclosuresFairValueDisclosuresUnobservableInputsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/FairValueDisclosuresTables" xlink:href="smbk-20190331.xsd#FairValueDisclosuresTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/Leases" xlink:href="smbk-20190331.xsd#Leases" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LeasesFutureMinimumPaymentsDetails" xlink:href="smbk-20190331.xsd#LeasesFutureMinimumPaymentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LeasesLeaseAssetsAndLiabilitiesDetails" xlink:href="smbk-20190331.xsd#LeasesLeaseAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LeasesLeaseCostsAndOtherInformationDetails" xlink:href="smbk-20190331.xsd#LeasesLeaseCostsAndOtherInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LeasesNarrativeDetails" xlink:href="smbk-20190331.xsd#LeasesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LeasesTables" xlink:href="smbk-20190331.xsd#LeasesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLosses" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLosses" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAccretableYieldRollForwardDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesAccretableYieldRollForwardDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAllByLoanClassificationDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesAllByLoanClassificationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAllRollForwardDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesAllRollForwardDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesImpairedLoanPortfolioDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesImpairedLoanPortfolioDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesLoanRiskRatingDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesLoanRiskRatingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesLoanSummaryDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesLoanSummaryDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesNarrativeDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPastDueLoansDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesPastDueLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPerformingAndImpairedLoansDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesPerformingAndImpairedLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPurchasedCreditImpairedLoansDetails" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesPurchasedCreditImpairedLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesTables" xlink:href="smbk-20190331.xsd#LoansAndAllowanceForLoanLossesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/PresentationOfFinancialInformation" xlink:href="smbk-20190331.xsd#PresentationOfFinancialInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/PresentationOfFinancialInformationDetails" xlink:href="smbk-20190331.xsd#PresentationOfFinancialInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/PresentationOfFinancialInformationPolicies" xlink:href="smbk-20190331.xsd#PresentationOfFinancialInformationPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/Securities" xlink:href="smbk-20190331.xsd#Securities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SecuritiesAmortizedCostAndFairValueOfAvailableForSaleSecuritiesDetails" xlink:href="smbk-20190331.xsd#SecuritiesAmortizedCostAndFairValueOfAvailableForSaleSecuritiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SecuritiesAvailableForSaleSecuritiesByContractualMaturityDetails" xlink:href="smbk-20190331.xsd#SecuritiesAvailableForSaleSecuritiesByContractualMaturityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SecuritiesAvailableForSaleSecuritiesInContinuousLossPositionDetails" xlink:href="smbk-20190331.xsd#SecuritiesAvailableForSaleSecuritiesInContinuousLossPositionDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SecuritiesNarrativeDetails" xlink:href="smbk-20190331.xsd#SecuritiesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SecuritiesTables" xlink:href="smbk-20190331.xsd#SecuritiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SubsequentEvents" xlink:href="smbk-20190331.xsd#SubsequentEvents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.smartbank.com/role/SubsequentEventsDetails" xlink:href="smbk-20190331.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/CommitmentsAndContingentLiabilities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/CommitmentsAndContingentLiabilitiesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/CommitmentsAndContingentLiabilitiesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedBalanceSheets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedStatementOfChangesInStockholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_9C761712EB9A0BBE9336943560DF5103" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_10991636B8FB83296176943560DE8DAD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9C761712EB9A0BBE9336943560DF5103" xlink:to="loc_us-gaap_StatementTable_10991636B8FB83296176943560DE8DAD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_47AF4C911D9A98337121943560DE1F66" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_10991636B8FB83296176943560DE8DAD" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_47AF4C911D9A98337121943560DE1F66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_47AF4C911D9A98337121943560DE1F66" xlink:to="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_47AF4C911D9A98337121943560DE1F66" xlink:to="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_2DCC979DD0A9509EDBC9943560DF1D1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:to="loc_us-gaap_CommonStockMember_2DCC979DD0A9509EDBC9943560DF1D1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_731FACBCB2A3A6F32EB8943560DF13BB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_731FACBCB2A3A6F32EB8943560DF13BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_4A532F7EFECACD755608943560DFDC3E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:to="loc_us-gaap_RetainedEarningsMember_4A532F7EFECACD755608943560DFDC3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_32DF7076A92A6479FD5B943560DF6277" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_B2930750C66CB74915CF943560DE501B" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_32DF7076A92A6479FD5B943560DF6277" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9C761712EB9A0BBE9336943560DF5103" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_E29447ABD047034C9390943560E05D4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_StockholdersEquity_E29447ABD047034C9390943560E05D4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_F6D497271B74627E6198943560E0C44B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_NetIncomeLoss_F6D497271B74627E6198943560E0C44B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_56711F3D1B55C5349A58943560E001CB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_56711F3D1B55C5349A58943560E001CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_1EBF886A4B0091DF7A0E943560E0C398" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_1EBF886A4B0091DF7A0E943560E0C398" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercisedNetOfTaxBenefitExpense" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercisedNetOfTaxBenefitExpense_C71CC9E485C4094A1D66943560E0C151" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercisedNetOfTaxBenefitExpense_C71CC9E485C4094A1D66943560E0C151" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition_CFB96152FD8A2B9CAE94943560E109D9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_32A975595D910385D696943560E06B68" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition_CFB96152FD8A2B9CAE94943560E109D9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/ConsolidatedStatementsOfIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/Derivatives" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DerivativesFairValueHedgesInBalanceSheetDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DerivativesFairValueHedgesOnBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_F16984A7ECBB2E0BA8168DF640FA52A9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_F16984A7ECBB2E0BA8168DF640FA52A9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_13178B867E08B1245ED28DF640FA2224" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_F16984A7ECBB2E0BA8168DF640FA52A9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_13178B867E08B1245ED28DF640FA2224" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_911656112AE98822E5298DF640FAE4DE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_13178B867E08B1245ED28DF640FA2224" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_911656112AE98822E5298DF640FAE4DE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_911656112AE98822E5298DF640FAE4DE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_13178B867E08B1245ED28DF640FA2224" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_911656112AE98822E5298DF640FAE4DE" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_InterestRateSwapLiabilityMember" xlink:label="loc_smbk_InterestRateSwapLiabilityMember_F735CADEE79EA0444EE88DF640FBA16A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_911656112AE98822E5298DF640FAE4DE" xlink:to="loc_smbk_InterestRateSwapLiabilityMember_F735CADEE79EA0444EE88DF640FBA16A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_955B2C7A17FDD3C9E7B28DF640FB3867" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_F16984A7ECBB2E0BA8168DF640FA52A9" xlink:to="loc_us-gaap_HedgingDesignationAxis_955B2C7A17FDD3C9E7B28DF640FB3867" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_7B09646C9671E37A7F4C8DF640FBD9EE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_955B2C7A17FDD3C9E7B28DF640FB3867" xlink:to="loc_us-gaap_HedgingDesignationDomain_7B09646C9671E37A7F4C8DF640FBD9EE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_7B09646C9671E37A7F4C8DF640FBD9EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_955B2C7A17FDD3C9E7B28DF640FB3867" xlink:to="loc_us-gaap_HedgingDesignationDomain_7B09646C9671E37A7F4C8DF640FBD9EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_66428475517A1BC41BB08DF640FB61B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_7B09646C9671E37A7F4C8DF640FBD9EE" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_66428475517A1BC41BB08DF640FB61B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeAverageRemainingMaturity1" xlink:label="loc_us-gaap_DerivativeAverageRemainingMaturity1_3621B92601E37B7B29E68DF640FC21B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:to="loc_us-gaap_DerivativeAverageRemainingMaturity1_3621B92601E37B7B29E68DF640FC21B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeAverageVariableInterestRate" xlink:label="loc_us-gaap_DerivativeAverageVariableInterestRate_03D235974FE9FD9F57F18DF640FC240C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:to="loc_us-gaap_DerivativeAverageVariableInterestRate_03D235974FE9FD9F57F18DF640FC240C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_D15D481173EE45BC44068DF640FC27F1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_D15D481173EE45BC44068DF640FC27F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgedLiabilityFairValueHedge" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedge_9CC1955F3B92BC6340F48DF640FDC44E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_CE241B83AB162EFA0DD18DF640FCD8E9" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedge_9CC1955F3B92BC6340F48DF640FDC44E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DerivativesFairValueHedgesOnIncomeStatementDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5C9BFFF63299B942692889BDD17FE9C3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_9E871F7F2D31BE90AB6D89BDD17DB981" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5C9BFFF63299B942692889BDD17FE9C3" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_9E871F7F2D31BE90AB6D89BDD17DB981" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_2CC4AB5DB65322C12E8989BDD17DAB1C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_9E871F7F2D31BE90AB6D89BDD17DB981" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_2CC4AB5DB65322C12E8989BDD17DAB1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_B6C7E96D5500977632F089BDD17E9FE4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2CC4AB5DB65322C12E8989BDD17DAB1C" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_B6C7E96D5500977632F089BDD17E9FE4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_B6C7E96D5500977632F089BDD17E9FE4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2CC4AB5DB65322C12E8989BDD17DAB1C" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_B6C7E96D5500977632F089BDD17E9FE4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_05D46593569BE217542A89BDD17E65D7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_B6C7E96D5500977632F089BDD17E9FE4" xlink:to="loc_us-gaap_InterestRateSwapMember_05D46593569BE217542A89BDD17E65D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_E8B239C828C610AE3F3489BDD17E9E8D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_9E871F7F2D31BE90AB6D89BDD17DB981" xlink:to="loc_us-gaap_HedgingDesignationAxis_E8B239C828C610AE3F3489BDD17E9E8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_EA8214CCDE989B8E542289BDD17F2C35_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_E8B239C828C610AE3F3489BDD17E9E8D" xlink:to="loc_us-gaap_HedgingDesignationDomain_EA8214CCDE989B8E542289BDD17F2C35_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_EA8214CCDE989B8E542289BDD17F2C35" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_E8B239C828C610AE3F3489BDD17E9E8D" xlink:to="loc_us-gaap_HedgingDesignationDomain_EA8214CCDE989B8E542289BDD17F2C35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_41950E1C571D2E55E1F089BDD17FA2B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_EA8214CCDE989B8E542289BDD17F2C35" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_41950E1C571D2E55E1F089BDD17FA2B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeOperating" xlink:label="loc_us-gaap_InterestIncomeOperating_DEE925B811DD1558818C89BDD17FCBCE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5C9BFFF63299B942692889BDD17FE9C3" xlink:to="loc_us-gaap_InterestIncomeOperating_DEE925B811DD1558818C89BDD17FCBCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_00B8A4FA18772F1A4BAE89BDD17FA93A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5C9BFFF63299B942692889BDD17FE9C3" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_00B8A4FA18772F1A4BAE89BDD17FA93A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DerivativesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_FF4CB74863E97423711B7A41E8161659" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_6A567A89DE6DB73B9D167A41E814043C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_FF4CB74863E97423711B7A41E8161659" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_6A567A89DE6DB73B9D167A41E814043C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_02E428E279D5230726E47A41E8140720" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_6A567A89DE6DB73B9D167A41E814043C" xlink:to="loc_us-gaap_HedgingDesignationAxis_02E428E279D5230726E47A41E8140720" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_FEECA049EE2C42592A577A41E8144920_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_02E428E279D5230726E47A41E8140720" xlink:to="loc_us-gaap_HedgingDesignationDomain_FEECA049EE2C42592A577A41E8144920_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_FEECA049EE2C42592A577A41E8144920" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_02E428E279D5230726E47A41E8140720" xlink:to="loc_us-gaap_HedgingDesignationDomain_FEECA049EE2C42592A577A41E8144920" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_BD69F94D0C603336B6E07A41E815D81A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_FEECA049EE2C42592A577A41E8144920" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_BD69F94D0C603336B6E07A41E815D81A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_1722EC0A731A565AD6EF7A41E815F179" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_6A567A89DE6DB73B9D167A41E814043C" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_1722EC0A731A565AD6EF7A41E815F179" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4EFF333675F91A1AD5517A41E8155052_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1722EC0A731A565AD6EF7A41E815F179" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4EFF333675F91A1AD5517A41E8155052_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4EFF333675F91A1AD5517A41E8155052" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1722EC0A731A565AD6EF7A41E815F179" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4EFF333675F91A1AD5517A41E8155052" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_551C82BFDCA7231177A17A41E815B465" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EFF333675F91A1AD5517A41E8155052" xlink:to="loc_us-gaap_InterestRateSwapMember_551C82BFDCA7231177A17A41E815B465" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld" xlink:label="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_1220667ECB040639216E7A41E8164F32" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_FF4CB74863E97423711B7A41E8161659" xlink:to="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_1220667ECB040639216E7A41E8164F32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_0B554E334A966D63068A7A41E816D7B3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_FF4CB74863E97423711B7A41E8161659" xlink:to="loc_invest_DerivativeNotionalAmount_0B554E334A966D63068A7A41E816D7B3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DerivativesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/EarningsPerShare" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/EarningsPerShareBasicAndDilutedDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/EarningsPerShareNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/EarningsPerShareTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosures" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnNonrecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_DE975AAE871A51E09D6C026F0AD78FAC" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D5AF30125B62532C984F1F1AD56A2270" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_DE975AAE871A51E09D6C026F0AD78FAC" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D5AF30125B62532C984F1F1AD56A2270" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87C4430473F2524FBE066CBE54A49BB4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_D5AF30125B62532C984F1F1AD56A2270" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87C4430473F2524FBE066CBE54A49BB4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_379B0800BF2D21C0A417F6C0145E6B2C_A580D87C70E8577C9CC04B976E16ECA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87C4430473F2524FBE066CBE54A49BB4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_379B0800BF2D21C0A417F6C0145E6B2C_A580D87C70E8577C9CC04B976E16ECA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B689EBFB9B6B58869A36D1C9E5AE89EF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87C4430473F2524FBE066CBE54A49BB4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B689EBFB9B6B58869A36D1C9E5AE89EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_0F78C32280CD53FE8ED43ED8A820ADC5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B689EBFB9B6B58869A36D1C9E5AE89EF" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_0F78C32280CD53FE8ED43ED8A820ADC5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_5D25F0B92CFE5F05A9EF29C0BEFF0B1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B689EBFB9B6B58869A36D1C9E5AE89EF" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_5D25F0B92CFE5F05A9EF29C0BEFF0B1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_BC89080E92DD5F5CB309905594776F09" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B689EBFB9B6B58869A36D1C9E5AE89EF" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_BC89080E92DD5F5CB309905594776F09" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ImpairedLoansFairValueDisclosure" xlink:label="loc_smbk_ImpairedLoansFairValueDisclosure_A0C2E8F1E3E35A89A7AF7FEE757CD319" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_DE975AAE871A51E09D6C026F0AD78FAC" xlink:to="loc_smbk_ImpairedLoansFairValueDisclosure_A0C2E8F1E3E35A89A7AF7FEE757CD319" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ForeclosedAssetsFairValue" xlink:label="loc_smbk_ForeclosedAssetsFairValue_148AC0B7CFD251EC97E8C1E4A5AC1EE5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_DE975AAE871A51E09D6C026F0AD78FAC" xlink:to="loc_smbk_ForeclosedAssetsFairValue_148AC0B7CFD251EC97E8C1E4A5AC1EE5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_73EA8F03E12C1A66C7D47A3B5214D5B2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_2D9DDB06F72AD3EB50957A3B5211A851" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_73EA8F03E12C1A66C7D47A3B5214D5B2" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_2D9DDB06F72AD3EB50957A3B5211A851" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_A5AD5A12FBB6EC70FB9E7A3B52111A1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_2D9DDB06F72AD3EB50957A3B5211A851" xlink:to="loc_us-gaap_FinancialInstrumentAxis_A5AD5A12FBB6EC70FB9E7A3B52111A1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_A5AD5A12FBB6EC70FB9E7A3B52111A1A" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_A5AD5A12FBB6EC70FB9E7A3B52111A1A" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_CC7FED06C88E3F89F33A7A3B5212A3F1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_CC7FED06C88E3F89F33A7A3B5212A3F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_3DF1E7C7C91F1D411D357A3B5213EC14" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_3DF1E7C7C91F1D411D357A3B5213EC14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherDebtSecuritiesMember" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_847FD7E38C58818F3ACB7A3B52136A18" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_847FD7E38C58818F3ACB7A3B52136A18" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_MunicipalSecuritiesMember" xlink:label="loc_smbk_MunicipalSecuritiesMember_416E861F90A22BAC6BB87A3B52134391" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E6974EBC70565E11CAAD7A3B52127794" xlink:to="loc_smbk_MunicipalSecuritiesMember_416E861F90A22BAC6BB87A3B52134391" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D08887EEFCC50D1ACE717A3B5213E455" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_2D9DDB06F72AD3EB50957A3B5211A851" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D08887EEFCC50D1ACE717A3B5213E455" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D08887EEFCC50D1ACE717A3B5213E455" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D08887EEFCC50D1ACE717A3B5213E455" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_E32D7AE1A7D262D6E55F7A3B52146A4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_E32D7AE1A7D262D6E55F7A3B52146A4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_90A3BC256A759F0872257A3B52146578" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_90A3BC256A759F0872257A3B52146578" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_FD35DB86FDF9DA8A3B777A3B52147D4A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_AE3058C924A375FC38EB7A3B52138996" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_FD35DB86FDF9DA8A3B777A3B52147D4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_B7150FDC45922B19A49C7A3B5214F0BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_73EA8F03E12C1A66C7D47A3B5214D5B2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_B7150FDC45922B19A49C7A3B5214F0BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_7F6B31132785E7310F807A3D04B6ABB3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_73EA8F03E12C1A66C7D47A3B5214D5B2" xlink:to="loc_us-gaap_DerivativeLiabilities_7F6B31132785E7310F807A3D04B6ABB3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosuresCarryingAmountAndEstimatedFairValueOfFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_BBF0E3704D9D6029D7DE7A3D8CE88E9D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_427B618E4486FD707D757A3D8CE53B83" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_BBF0E3704D9D6029D7DE7A3D8CE88E9D" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_427B618E4486FD707D757A3D8CE53B83" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_27D6480CCC37AAD15AD67A3D8CE524A6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_427B618E4486FD707D757A3D8CE53B83" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_27D6480CCC37AAD15AD67A3D8CE524A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0BF2AFC7871D8BE217D97A3D8CE6AAAF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_27D6480CCC37AAD15AD67A3D8CE524A6" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0BF2AFC7871D8BE217D97A3D8CE6AAAF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_77FB05D97C07654CE6D77A3D8CE5623E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_27D6480CCC37AAD15AD67A3D8CE524A6" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_77FB05D97C07654CE6D77A3D8CE5623E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0BF2AFC7871D8BE217D97A3D8CE6AAAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_77FB05D97C07654CE6D77A3D8CE5623E" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0BF2AFC7871D8BE217D97A3D8CE6AAAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_6BA73CB8F9DF0C839D9F7A3D8CE663A2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_77FB05D97C07654CE6D77A3D8CE5623E" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_6BA73CB8F9DF0C839D9F7A3D8CE663A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_60773C0C2CCBE3146A7B7A3D8CE6C117" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_77FB05D97C07654CE6D77A3D8CE5623E" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_60773C0C2CCBE3146A7B7A3D8CE6C117" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_34BB6418F832E24175377A3D8CE6CD2F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_427B618E4486FD707D757A3D8CE53B83" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_34BB6418F832E24175377A3D8CE6CD2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_34BB6418F832E24175377A3D8CE6CD2F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_34BB6418F832E24175377A3D8CE6CD2F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_1D8E04E38E1C03A0C8E57A3D8CE74BBE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_1D8E04E38E1C03A0C8E57A3D8CE74BBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_79157E8CE10D9A25649C7A3D8CE716AC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_79157E8CE10D9A25649C7A3D8CE716AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_A0872DB92FB4C0591FCC7A3D8CE7CD5D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1E6F82B4F6E2CC3D92167A3D8CE7D95C" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_A0872DB92FB4C0591FCC7A3D8CE7CD5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_BBF0E3704D9D6029D7DE7A3D8CE88E9D" xlink:to="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_0FC4684FEF54D5EE0EDD7A3D8CE82D81" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_0FC4684FEF54D5EE0EDD7A3D8CE82D81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_552D5B2367928C813AF17A3D8CE802EF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_552D5B2367928C813AF17A3D8CE802EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentOwnedRestrictedCost" xlink:label="loc_us-gaap_InvestmentOwnedRestrictedCost_16D4E688A934DBE11CA47A3D8CE86326" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:to="loc_us-gaap_InvestmentOwnedRestrictedCost_16D4E688A934DBE11CA47A3D8CE86326" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_9715593EA941D3F5381D7A3D8CE99524" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_43D253047F1F1A56A9CA7A3D8CE8835A" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_9715593EA941D3F5381D7A3D8CE99524" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAbstract" xlink:label="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_BBF0E3704D9D6029D7DE7A3D8CE88E9D" xlink:to="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestBearingDepositLiabilities" xlink:label="loc_us-gaap_NoninterestBearingDepositLiabilities_7246EC8DFFCD902E974B7A3D8CE99CE6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_NoninterestBearingDepositLiabilities_7246EC8DFFCD902E974B7A3D8CE99CE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DemandDepositAccounts" xlink:label="loc_us-gaap_DemandDepositAccounts_EA1709E7B9B41205C62F7A3D8CE986A6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_DemandDepositAccounts_EA1709E7B9B41205C62F7A3D8CE986A6" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_SavingsDepositsAndMoneyMarketAccountsFairValue" xlink:label="loc_smbk_SavingsDepositsAndMoneyMarketAccountsFairValue_AB4ED536566418D854587A3D8CE93C4E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_smbk_SavingsDepositsAndMoneyMarketAccountsFairValue_AB4ED536566418D854587A3D8CE93C4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDeposits" xlink:label="loc_us-gaap_TimeDeposits_117EC534DB256AA26D867A3D8CEA7D92" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_TimeDeposits_117EC534DB256AA26D867A3D8CEA7D92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure" xlink:label="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_923B145A2727E0F3CFF37A3D8CEA2233" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_923B145A2727E0F3CFF37A3D8CEA2233" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_C6C25FC674F867797BFC7A3D8CEAD96B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_C6C25FC674F867797BFC7A3D8CEAD96B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_6A539E01C3948730C6E27A3D8CEA63F3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_6A539E01C3948730C6E27A3D8CEA63F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_DCFB68A32889A495094C7A3D8D6985D7" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_55EA5A687F2B65FBBAAA7A3D8CE943C6" xlink:to="loc_us-gaap_DerivativeLiabilities_DCFB68A32889A495094C7A3D8D6985D7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosuresFairValueDisclosuresUnobservableInputsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_71B193DDBE5352282B548DF64165429C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_71B193DDBE5352282B548DF64165429C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_B811F5304470A3AD77E38DF64165C7C7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_71B193DDBE5352282B548DF64165429C" xlink:to="loc_srt_RangeAxis_B811F5304470A3AD77E38DF64165C7C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_69C70B3D0A80FBE6C0EE8DF64166E029_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_B811F5304470A3AD77E38DF64165C7C7" xlink:to="loc_srt_RangeMember_69C70B3D0A80FBE6C0EE8DF64166E029_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_69C70B3D0A80FBE6C0EE8DF64166E029" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_B811F5304470A3AD77E38DF64165C7C7" xlink:to="loc_srt_RangeMember_69C70B3D0A80FBE6C0EE8DF64166E029" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_WeightedAverageMember" xlink:label="loc_srt_WeightedAverageMember_E6414BFFAA9BD90C4EA78DF64166E995" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_69C70B3D0A80FBE6C0EE8DF64166E029" xlink:to="loc_srt_WeightedAverageMember_E6414BFFAA9BD90C4EA78DF64166E995" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87AF0D306FBE0D2F1E5A8DF6416615FC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_71B193DDBE5352282B548DF64165429C" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87AF0D306FBE0D2F1E5A8DF6416615FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A91BF89B0617A572C7938DF64166B0E9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87AF0D306FBE0D2F1E5A8DF6416615FC" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A91BF89B0617A572C7938DF64166B0E9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A91BF89B0617A572C7938DF64166B0E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87AF0D306FBE0D2F1E5A8DF6416615FC" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A91BF89B0617A572C7938DF64166B0E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_D4DD86ECD1A8590136328DF6416765B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_A91BF89B0617A572C7938DF64166B0E9" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_D4DD86ECD1A8590136328DF6416765B5" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ImpairedLoansFairValueDisclosure" xlink:label="loc_smbk_ImpairedLoansFairValueDisclosure_2336694883698FF41D348DF641678B86" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:to="loc_smbk_ImpairedLoansFairValueDisclosure_2336694883698FF41D348DF641678B86" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ImpairedLoansMeasurementInput" xlink:label="loc_smbk_ImpairedLoansMeasurementInput_6467BB9E4C304387605A8DF64167475E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:to="loc_smbk_ImpairedLoansMeasurementInput_6467BB9E4C304387605A8DF64167475E" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ForeclosedAssetsFairValue" xlink:label="loc_smbk_ForeclosedAssetsFairValue_4B92116393BDBB16EFBB8DF64168E72A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:to="loc_smbk_ForeclosedAssetsFairValue_4B92116393BDBB16EFBB8DF64168E72A" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ForeclosedAssetsMeasurementInput" xlink:label="loc_smbk_ForeclosedAssetsMeasurementInput_F5765BF38366DF66FF1C8DF641685D02" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_7162D932C9A1518D31AB8DF641679992" xlink:to="loc_smbk_ForeclosedAssetsMeasurementInput_F5765BF38366DF66FF1C8DF641685D02" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/FairValueDisclosuresTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/Leases" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LeasesFutureMinimumPaymentsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LeasesLeaseAssetsAndLiabilitiesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LeasesLeaseCostsAndOtherInformationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LeasesNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LeasesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLosses" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAccretableYieldRollForwardDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleLineItems" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleLineItems_63E6E12E5E30E9E8176A996F35A5D726" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleTable" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleTable_2080EE0D4F37D4FED00A996F35A4A9AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleLineItems_63E6E12E5E30E9E8176A996F35A5D726" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleTable_2080EE0D4F37D4FED00A996F35A4A9AA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_49EE4811C33B0960FE4A996F35A4FE8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleTable_2080EE0D4F37D4FED00A996F35A4A9AA" xlink:to="loc_us-gaap_CreditLossStatusAxis_49EE4811C33B0960FE4A996F35A4FE8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_387823653DD3EF2E1109996F35A56D2A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_49EE4811C33B0960FE4A996F35A4FE8F" xlink:to="loc_us-gaap_CreditLossStatusDomain_387823653DD3EF2E1109996F35A56D2A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_387823653DD3EF2E1109996F35A56D2A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_49EE4811C33B0960FE4A996F35A4FE8F" xlink:to="loc_us-gaap_CreditLossStatusDomain_387823653DD3EF2E1109996F35A56D2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_38F50D6C9D191EBA42AD996F35A5FE53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_387823653DD3EF2E1109996F35A56D2A" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_38F50D6C9D191EBA42AD996F35A5FE53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleLineItems_63E6E12E5E30E9E8176A996F35A5D726" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYield" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYield_84C5F4E86B6AB7619F22996F35A6C7E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYield_84C5F4E86B6AB7619F22996F35A6C7E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAdditions" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAdditions_9B7C3E05A9BE006A0539996F35A6E155" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAdditions_9B7C3E05A9BE006A0539996F35A6E155" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion_0213FED425121528329D996F35A68547" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion_0213FED425121528329D996F35A68547" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsToFromNonaccretableDifference" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsToFromNonaccretableDifference_D366BF0744FA1ED9A110996F35A6B128" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsToFromNonaccretableDifference_D366BF0744FA1ED9A110996F35A6B128" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease_82D9BCAB348675485D1F996F35A71768" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_EAEFEB1648E9D1D7999A996F35A53400" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease_82D9BCAB348675485D1F996F35A71768" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAllByLoanClassificationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_78CDE26384FD5432651A996F35E1686E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_90396037D82BC00CAA5A996F35DD6620" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_78CDE26384FD5432651A996F35E1686E" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_90396037D82BC00CAA5A996F35DD6620" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_24133CD8ABD42B09B4B4996F35DE25DD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_90396037D82BC00CAA5A996F35DD6620" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_24133CD8ABD42B09B4B4996F35DE25DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_24133CD8ABD42B09B4B4996F35DE25DD" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_24133CD8ABD42B09B4B4996F35DE25DD" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_192113C2F621B3D26DDC996F35DED5D3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_192113C2F621B3D26DDC996F35DED5D3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_00A174C1F8B68D05B5DB996F35DE1C29" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_00A174C1F8B68D05B5DB996F35DE1C29" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_B051FD8401264E638793996F35DF0B15" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_B051FD8401264E638793996F35DF0B15" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_51A2D012874B54206EB6996F35DF7438" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_51A2D012874B54206EB6996F35DF7438" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_1BDC4D9DC70B62E8D6F9996F35DF9BD1" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_027A6586CE2BA11D5FAF996F35DE5491" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_1BDC4D9DC70B62E8D6F9996F35DF9BD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_F9A032BAD0E9592E62FD996F35DF10B5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_90396037D82BC00CAA5A996F35DD6620" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_F9A032BAD0E9592E62FD996F35DF10B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_F9A032BAD0E9592E62FD996F35DF10B5" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_F9A032BAD0E9592E62FD996F35DF10B5" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PerformingFinancingReceivableMember" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_4C36B68DC35DCDE9446A996F35DF4C61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_4C36B68DC35DCDE9446A996F35DF4C61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NonperformingFinancingReceivableMember" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_334A896FED2B94B6727D996F35E03133" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_C232D807F0070656B0A5996F35DFB63A" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_334A896FED2B94B6727D996F35E03133" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_5F9AE8FCAAD7E347913E996F35E050BB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_90396037D82BC00CAA5A996F35DD6620" xlink:to="loc_us-gaap_CreditLossStatusAxis_5F9AE8FCAAD7E347913E996F35E050BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_5F9AE8FCAAD7E347913E996F35E050BB" xlink:to="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_5F9AE8FCAAD7E347913E996F35E050BB" xlink:to="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember" xlink:label="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_4D188CADFCBEEB16F52A996F35E0FF3C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB" xlink:to="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_4D188CADFCBEEB16F52A996F35E0FF3C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_D184A6B0C69F527455E4996F35E1ED16" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_CB81248A8581150E1ADD996F35E0A5BB" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_D184A6B0C69F527455E4996F35E1ED16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_BAA9C0990695E2599A94996F35E1C2A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_78CDE26384FD5432651A996F35E1686E" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_BAA9C0990695E2599A94996F35E1C2A1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesAllRollForwardDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_15DF379F7867C99ABB7D996F35D7665E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_ECEADE64B85DB77C355D996F35D63720" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_15DF379F7867C99ABB7D996F35D7665E" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_ECEADE64B85DB77C355D996F35D63720" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_D9016E0E546A397645DC996F35D674EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_ECEADE64B85DB77C355D996F35D63720" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_D9016E0E546A397645DC996F35D674EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_D9016E0E546A397645DC996F35D674EE" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_D9016E0E546A397645DC996F35D674EE" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_3B3CCB5C12A6074155F8996F35D71AE4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_3B3CCB5C12A6074155F8996F35D71AE4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_ECC58C5B6D66B6FA3CFA996F35D7AD86" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_ECC58C5B6D66B6FA3CFA996F35D7AD86" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_5EAA09F8A5E2386897D9996F35D7107E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_5EAA09F8A5E2386897D9996F35D7107E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_AC7372292C01A90FABD3996F35D75D6B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_AC7372292C01A90FABD3996F35D75D6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_B8373E2DBE7441283F56996F35D7F4F7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8AF2B886354D38CE088D996F35D6B8CB" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_B8373E2DBE7441283F56996F35D7F4F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesRollForward" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_15DF379F7867C99ABB7D996F35D7665E" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_8721F32927CC6CA341DA996F35D878AB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_8721F32927CC6CA341DA996F35D878AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_F64A07FDDEF5D2F8C2A6996F35D85E0E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_F64A07FDDEF5D2F8C2A6996F35D85E0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_55EE350F81BD8BD0F7B4996F35D89FEF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_55EE350F81BD8BD0F7B4996F35D89FEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanAndLeaseLosses" xlink:label="loc_us-gaap_ProvisionForLoanAndLeaseLosses_41613FF4259B64683806996F35D9C95D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_1FAEE0BF294726D23B46996F35D89A5A" xlink:to="loc_us-gaap_ProvisionForLoanAndLeaseLosses_41613FF4259B64683806996F35D9C95D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesImpairedLoanPortfolioDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableImpairedLineItems" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_0A8B0C4144994A1DF027996F35B603B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_0A8B0C4144994A1DF027996F35B603B0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_0A98F24B734A6EC16DB4996F35B7ACA8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_0A8B0C4144994A1DF027996F35B603B0" xlink:to="loc_us-gaap_CreditLossStatusAxis_0A98F24B734A6EC16DB4996F35B7ACA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_0A98F24B734A6EC16DB4996F35B7ACA8" xlink:to="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_0A98F24B734A6EC16DB4996F35B7ACA8" xlink:to="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember" xlink:label="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_468C677B3CAD5EFBD2D4996F35B775B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021" xlink:to="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_468C677B3CAD5EFBD2D4996F35B775B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_8F6FDF87938D6F18A3B7996F35B8AD5C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_11C68CAC08B3A945840E996F35B74021" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_8F6FDF87938D6F18A3B7996F35B8AD5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_987DD82423E5447276D5996F35B865B3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_0A8B0C4144994A1DF027996F35B603B0" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_987DD82423E5447276D5996F35B865B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_987DD82423E5447276D5996F35B865B3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_987DD82423E5447276D5996F35B865B3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_707DEC35A28B83AE30BC996F35B847F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_707DEC35A28B83AE30BC996F35B847F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_AB3AB0FCE3445FD081F6996F35B8F671" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_AB3AB0FCE3445FD081F6996F35B8F671" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_D1D104A991F9196BEAC4996F35B94D95" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_D1D104A991F9196BEAC4996F35B94D95" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_FA8CF6ECA763F0997357996F35B987B9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_FA8CF6ECA763F0997357996F35B987B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_C0CFB8362E0FFF5DAB2E996F35B90F2A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_A218642E22F10FD62031996F35B8C8DB" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_C0CFB8362E0FFF5DAB2E996F35B90F2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_E1AAFB689F86190B3358996F35B9400C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_E1AAFB689F86190B3358996F35B9400C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_7BE1F2FD5869F8987267996F35BA3617" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_7BE1F2FD5869F8987267996F35BA3617" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_799F802CB79DABAAA5F1996F35BACB56" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_799F802CB79DABAAA5F1996F35BACB56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod_959869BFD48E6EEF28F4996F35BA1D57" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod_959869BFD48E6EEF28F4996F35BA1D57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_760A0D93D5A5A7CBCB16996F35BA2FBE" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_760A0D93D5A5A7CBCB16996F35BA2FBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_3EE980D12821F8A2D505996F35BA9AEC" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_3EE980D12821F8A2D505996F35BA9AEC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_390666B45A22FA8C0FC9996F35BA9B9C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_390666B45A22FA8C0FC9996F35BA9B9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_CE06794A110EAE344166996F35BBB816" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_CE06794A110EAE344166996F35BBB816" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod_C81504D2798E1489ADD1996F35BB559C" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod_C81504D2798E1489ADD1996F35BB559C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_EB527FF07464BC41003F996F35BBB671" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_EB527FF07464BC41003F996F35BBB671" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_21F9A5BAC7047021B8F3996F35BB514D" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_21F9A5BAC7047021B8F3996F35BB514D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_1678F07C53616D9F6000996F35BB0A9E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_1678F07C53616D9F6000996F35BB0A9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod" xlink:label="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod_4E99F45BD4FF2CA6FA3F996F35BB9636" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_BE0FBC5B873D0EC0FE7C996F35B9CB3E" xlink:to="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod_4E99F45BD4FF2CA6FA3F996F35BB9636" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesLoanRiskRatingDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_3136ABA2B4B1DFFD94D0996F35D16215" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_1A18CF11B21857A35546996F35CD8CC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_3136ABA2B4B1DFFD94D0996F35D16215" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_1A18CF11B21857A35546996F35CD8CC4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_77717E023FF61F425A8C996F35CD3AE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_1A18CF11B21857A35546996F35CD8CC4" xlink:to="loc_us-gaap_CreditLossStatusAxis_77717E023FF61F425A8C996F35CD3AE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_77717E023FF61F425A8C996F35CD3AE2" xlink:to="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_77717E023FF61F425A8C996F35CD3AE2" xlink:to="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember" xlink:label="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_7F20A5642F895C5F2F54996F35CD7691" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566" xlink:to="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_7F20A5642F895C5F2F54996F35CD7691" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_C3BFCDE938AEF27D71F8996F35CE384D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_34177916FE7AF90F3635996F35CDF566" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_C3BFCDE938AEF27D71F8996F35CE384D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_8A63D3DC9E622BC53AAC996F35CE9C73" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_1A18CF11B21857A35546996F35CD8CC4" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_8A63D3DC9E622BC53AAC996F35CE9C73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_8A63D3DC9E622BC53AAC996F35CE9C73" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_8A63D3DC9E622BC53AAC996F35CE9C73" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_565258E025CC18C99991996F35CEAA47" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_565258E025CC18C99991996F35CEAA47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_03C4DA07CF04B925B187996F35CFB1D8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_03C4DA07CF04B925B187996F35CFB1D8" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_6063CCB9B62A48A29D2A996F35CF4E25" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_6063CCB9B62A48A29D2A996F35CF4E25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_8FBC6662A1D8C957D4ED996F35CFB7BE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_8FBC6662A1D8C957D4ED996F35CFB7BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_5388DF7B0A472653F45B996F35CFA7C3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_DF3CAB8C712935734501996F35CED6AE" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_5388DF7B0A472653F45B996F35CFA7C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentAxis" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_AE88FBC149ADE3C5572A996F35CF8167" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_1A18CF11B21857A35546996F35CD8CC4" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_AE88FBC149ADE3C5572A996F35CF8167" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentDomain" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_AE88FBC149ADE3C5572A996F35CF8167" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentDomain" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_AE88FBC149ADE3C5572A996F35CF8167" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PassMember" xlink:label="loc_us-gaap_PassMember_5084681313C9BDA4FE7B996F35D06138" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:to="loc_us-gaap_PassMember_5084681313C9BDA4FE7B996F35D06138" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_WatchMember" xlink:label="loc_smbk_WatchMember_A88739B4F1EE1F870898996F35D02D1C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:to="loc_smbk_WatchMember_A88739B4F1EE1F870898996F35D02D1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SpecialMentionMember" xlink:label="loc_us-gaap_SpecialMentionMember_7C7A4AD308CB82F5FC2F996F35D0063F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:to="loc_us-gaap_SpecialMentionMember_7C7A4AD308CB82F5FC2F996F35D0063F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubstandardMember" xlink:label="loc_us-gaap_SubstandardMember_17DB8165B90CE821F4D9996F35D03F1F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:to="loc_us-gaap_SubstandardMember_17DB8165B90CE821F4D9996F35D03F1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DoubtfulMember" xlink:label="loc_us-gaap_DoubtfulMember_D3B7505C164CAA61A817996F35D0E3C0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_7E00E153F6E9B7754260996F35D0E2B1" xlink:to="loc_us-gaap_DoubtfulMember_D3B7505C164CAA61A817996F35D0E3C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_AFF1CD14E9BC430E5545996F35D18AD5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_3136ABA2B4B1DFFD94D0996F35D16215" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_AFF1CD14E9BC430E5545996F35D18AD5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesLoanSummaryDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_8D91B41F61F4B6583190996F35F78694" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FCE33AF81CA0B284812C996F35F4C089" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_8D91B41F61F4B6583190996F35F78694" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FCE33AF81CA0B284812C996F35F4C089" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1D7E73FB237803A92561996F35F47DB8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FCE33AF81CA0B284812C996F35F4C089" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1D7E73FB237803A92561996F35F47DB8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1D7E73FB237803A92561996F35F47DB8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1D7E73FB237803A92561996F35F47DB8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_CF9F9496A0D66E995132996F35F59E41" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_CF9F9496A0D66E995132996F35F59E41" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_EDE20ABAD5E04131BD54996F35F595FE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_EDE20ABAD5E04131BD54996F35F595FE" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_5108D58FB873393B6C87996F35F51BF2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_5108D58FB873393B6C87996F35F51BF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_D46AA31E6E0800BE4334996F35F58CF4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_D46AA31E6E0800BE4334996F35F58CF4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_1AF26485ED176C2FFD90996F35F61EC0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_69BDC831B2EE9B65BCC3996F35F4DE64" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_1AF26485ED176C2FFD90996F35F61EC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_AD7C4AC5D15E6B884CDA996F35F6C536" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FCE33AF81CA0B284812C996F35F4C089" xlink:to="loc_us-gaap_CreditLossStatusAxis_AD7C4AC5D15E6B884CDA996F35F6C536" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_AD7C4AC5D15E6B884CDA996F35F6C536" xlink:to="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_AD7C4AC5D15E6B884CDA996F35F6C536" xlink:to="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_306490DDE97580D6F000996F35F66873" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_306490DDE97580D6F000996F35F66873" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember" xlink:label="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_A57781083252F7AFB206996F35F6249F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_21BA69F71F499D253267996F35F69BCF" xlink:to="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_A57781083252F7AFB206996F35F6249F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_F243BF65F7C9F44FA9D2996F35F723A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_8D91B41F61F4B6583190996F35F78694" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_F243BF65F7C9F44FA9D2996F35F723A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_D80E5E0EBA8830B3DF09996F35F7E1A3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_8D91B41F61F4B6583190996F35F78694" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_D80E5E0EBA8830B3DF09996F35F7E1A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_58C4A6DDFAFECCA3A68D996F35F73CE1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_8D91B41F61F4B6583190996F35F78694" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_58C4A6DDFAFECCA3A68D996F35F73CE1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_CB3CDCD1C332A77EEAFD996F35EDE121" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_CB3CDCD1C332A77EEAFD996F35EDE121" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoanRestructuringModificationNameAxis" xlink:label="loc_us-gaap_LoanRestructuringModificationNameAxis_E17E99D92A65C170B3E9996F35EE1878" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_CB3CDCD1C332A77EEAFD996F35EDE121" xlink:to="loc_us-gaap_LoanRestructuringModificationNameAxis_E17E99D92A65C170B3E9996F35EE1878" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoanRestructuringModificationNameDomain" xlink:label="loc_us-gaap_LoanRestructuringModificationNameDomain_6923AA06BEFC4B253450996F35EE0927_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationNameAxis_E17E99D92A65C170B3E9996F35EE1878" xlink:to="loc_us-gaap_LoanRestructuringModificationNameDomain_6923AA06BEFC4B253450996F35EE0927_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoanRestructuringModificationNameDomain" xlink:label="loc_us-gaap_LoanRestructuringModificationNameDomain_6923AA06BEFC4B253450996F35EE0927" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationNameAxis_E17E99D92A65C170B3E9996F35EE1878" xlink:to="loc_us-gaap_LoanRestructuringModificationNameDomain_6923AA06BEFC4B253450996F35EE0927" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_TroubleDebtRestructuringMember" xlink:label="loc_smbk_TroubleDebtRestructuringMember_31FF0C069E889849E858996F35EEC4A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationNameDomain_6923AA06BEFC4B253450996F35EE0927" xlink:to="loc_smbk_TroubleDebtRestructuringMember_31FF0C069E889849E858996F35EEC4A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_5D81487967B585DF738E996F35EF8883" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_us-gaap_NumberOfReportableSegments_5D81487967B585DF738E996F35EF8883" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsRecordedInvestment" xlink:label="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_E0935937BA7A68655847996F35EF2B0A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_E0935937BA7A68655847996F35EF2B0A" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_FinancingReceivableNonaccrualNumberOfContracts" xlink:label="loc_smbk_FinancingReceivableNonaccrualNumberOfContracts_E84476BF86EA88E4C953996F35EFFDC0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_smbk_FinancingReceivableNonaccrualNumberOfContracts_E84476BF86EA88E4C953996F35EFFDC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_2BE9024D06A606AE2459996F35EF3A85" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_2BE9024D06A606AE2459996F35EF3A85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_42C75C9793A76A022D89996F35EFF47A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_552BC625D4CB5EB38C57996F35EE4EC2" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_42C75C9793A76A022D89996F35EFF47A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPastDueLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_2BA6766219FE7F69EF42996F35C37350" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_2BA6766219FE7F69EF42996F35C37350" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_6314AB32F7432B9D040B996F35C30B56" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_2BA6766219FE7F69EF42996F35C37350" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_6314AB32F7432B9D040B996F35C30B56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_6314AB32F7432B9D040B996F35C30B56" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_6314AB32F7432B9D040B996F35C30B56" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_FinancingReceivable30to60DaysPastDueMember" xlink:label="loc_smbk_FinancingReceivable30to60DaysPastDueMember_3DB3D5CD6FAC9BD54F56996F35C38A78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D" xlink:to="loc_smbk_FinancingReceivable30to60DaysPastDueMember_3DB3D5CD6FAC9BD54F56996F35C38A78" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_FinancingReceivable61to89DaysPastDueMember" xlink:label="loc_smbk_FinancingReceivable61to89DaysPastDueMember_E5F53CBF7F03A827629E996F35C4E2BE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D" xlink:to="loc_smbk_FinancingReceivable61to89DaysPastDueMember_E5F53CBF7F03A827629E996F35C4E2BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_3F94E7B72D73AB9F039D996F35C41B4E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_1FC0AF7361EB4A3A3C52996F35C3B43D" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_3F94E7B72D73AB9F039D996F35C41B4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_824656EFBC005024E525996F35C422DA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_2BA6766219FE7F69EF42996F35C37350" xlink:to="loc_us-gaap_CreditLossStatusAxis_824656EFBC005024E525996F35C422DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_BF899A12D181ADEE114E996F35C4CA9E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_824656EFBC005024E525996F35C422DA" xlink:to="loc_us-gaap_CreditLossStatusDomain_BF899A12D181ADEE114E996F35C4CA9E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_BF899A12D181ADEE114E996F35C4CA9E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_824656EFBC005024E525996F35C422DA" xlink:to="loc_us-gaap_CreditLossStatusDomain_BF899A12D181ADEE114E996F35C4CA9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_44BB04650F54BE64D32E996F35C48FB7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_BF899A12D181ADEE114E996F35C4CA9E" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_44BB04650F54BE64D32E996F35C48FB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_EDAAC7BF1BCE54D9A486996F35C53367" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_2BA6766219FE7F69EF42996F35C37350" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_EDAAC7BF1BCE54D9A486996F35C53367" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_EDAAC7BF1BCE54D9A486996F35C53367" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_EDAAC7BF1BCE54D9A486996F35C53367" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_3694185EC25FADBCD875996F35C591C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_3694185EC25FADBCD875996F35C591C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_224AA6EB5926FB0C0EB0996F35C51698" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_224AA6EB5926FB0C0EB0996F35C51698" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_C9F785FFD468211ECE45996F35C62E1C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_C9F785FFD468211ECE45996F35C62E1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_8921F7AE0492B767E4EC996F35C6222D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_8921F7AE0492B767E4EC996F35C6222D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_7D693BCBCE16088D112E996F35C675A4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_BB8B359E80862492CB56996F35C5059E" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_7D693BCBCE16088D112E996F35C675A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDue" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_B93111CAA2DB7BA2E139996F35C65E7C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_B93111CAA2DB7BA2E139996F35C65E7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_92857596D0335C42CC1B996F35C63568" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_92857596D0335C42CC1B996F35C63568" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_FinancingReceivableRecordedInvestmentPastDueIncludingNonaccrualStatus" xlink:label="loc_smbk_FinancingReceivableRecordedInvestmentPastDueIncludingNonaccrualStatus_CE809F99DC33C05581F9996F35C706DB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_smbk_FinancingReceivableRecordedInvestmentPastDueIncludingNonaccrualStatus_CE809F99DC33C05581F9996F35C706DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentCurrent" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_D7A88A0E5E1C85D5E3D3996F35C7124F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_D7A88A0E5E1C85D5E3D3996F35C7124F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_3416937FBA941C50FE43996F35C7E336" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_61857EEBF80F7FEB5918996F35C60FDA" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_3416937FBA941C50FE43996F35C7E336" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPerformingAndImpairedLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_B0A3CFAB2C08F9F29FC0996F35E9BB47" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_CF83EE4BFF23982932D9996F35E6A5F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_B0A3CFAB2C08F9F29FC0996F35E9BB47" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_CF83EE4BFF23982932D9996F35E6A5F5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_AB6C2B850D054B1F7A38996F35E6CF71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_CF83EE4BFF23982932D9996F35E6A5F5" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_AB6C2B850D054B1F7A38996F35E6CF71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_AB6C2B850D054B1F7A38996F35E6CF71" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_AB6C2B850D054B1F7A38996F35E6CF71" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PerformingFinancingReceivableMember" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_84319ED9C4B0080769B0996F35E745C8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_84319ED9C4B0080769B0996F35E745C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NonperformingFinancingReceivableMember" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_04044D01A91A6C31F484996F35E7C068" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_FDF5AA7E96CFC87E6F24996F35E6CB39" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_04044D01A91A6C31F484996F35E7C068" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5DF47DBE0EC9B18FA0B4996F35E70BCD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_CF83EE4BFF23982932D9996F35E6A5F5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5DF47DBE0EC9B18FA0B4996F35E70BCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5DF47DBE0EC9B18FA0B4996F35E70BCD" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5DF47DBE0EC9B18FA0B4996F35E70BCD" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_2634838C3081D81E72EC996F35E812E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_2634838C3081D81E72EC996F35E812E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_4FC8B6DDC5ED169E001A996F35E88DE2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_4FC8B6DDC5ED169E001A996F35E88DE2" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_8489B522624302EF3D3F996F35E8F16E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_8489B522624302EF3D3F996F35E8F16E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_221B7F03F460D94B3F05996F35E8FFD8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_221B7F03F460D94B3F05996F35E8FFD8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_B8116F148B5E8AAE355B996F35E8640D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0A14C147AD53B3754BBB996F35E78705" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_B8116F148B5E8AAE355B996F35E8640D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_7597A222E3F2E4931868996F35E83776" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_CF83EE4BFF23982932D9996F35E6A5F5" xlink:to="loc_us-gaap_CreditLossStatusAxis_7597A222E3F2E4931868996F35E83776" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_7597A222E3F2E4931868996F35E83776" xlink:to="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_7597A222E3F2E4931868996F35E83776" xlink:to="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember" xlink:label="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_E024B3294D56F93932D6996F35E9341E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1" xlink:to="loc_smbk_ReceivablesOtherthanReceivablesAcquiredwithDeterioratedCreditQualityMember_E024B3294D56F93932D6996F35E9341E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_709832C370C8B4EE25D0996F35E9874E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_64D03D7601E3B64E24B9996F35E9BAB1" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_709832C370C8B4EE25D0996F35E9874E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_4F6C081A57072175BFFF996F35E90613" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_B0A3CFAB2C08F9F29FC0996F35E9BB47" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_4F6C081A57072175BFFF996F35E90613" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesPurchasedCreditImpairedLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTable" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTable_F57060013259C0300635996F35AB6BF3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTable_F57060013259C0300635996F35AB6BF3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1449CF3B2FF2BCC91FD5996F35AC725F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTable_F57060013259C0300635996F35AB6BF3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1449CF3B2FF2BCC91FD5996F35AC725F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1449CF3B2FF2BCC91FD5996F35AC725F" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_1449CF3B2FF2BCC91FD5996F35AC725F" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_4B0103D3C08848A1D3CF996F35ACE362" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_4B0103D3C08848A1D3CF996F35ACE362" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_2521BA82332B9D10EBE7996F35AD891A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_2521BA82332B9D10EBE7996F35AD891A" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ConstructionPortfolioSegmentMember" xlink:label="loc_smbk_ConstructionPortfolioSegmentMember_1F3E7860DCD415F8CBAC996F35AD9445" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:to="loc_smbk_ConstructionPortfolioSegmentMember_1F3E7860DCD415F8CBAC996F35AD9445" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_BE17E6F2FC10E2DE2C98996F35ADCF91" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_BE17E6F2FC10E2DE2C98996F35ADCF91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_4540D7BAA1782503ED98996F35AD1F31" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_8B26D362D3A9DC3FB1A8996F35AC6541" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_4540D7BAA1782503ED98996F35AD1F31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusAxis" xlink:label="loc_us-gaap_CreditLossStatusAxis_110A28F297EDE2C5A099996F35ADBF54" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTable_F57060013259C0300635996F35AB6BF3" xlink:to="loc_us-gaap_CreditLossStatusAxis_110A28F297EDE2C5A099996F35ADBF54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_A522FE0E354F683107CD996F35AD1155_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditLossStatusAxis_110A28F297EDE2C5A099996F35ADBF54" xlink:to="loc_us-gaap_CreditLossStatusDomain_A522FE0E354F683107CD996F35AD1155_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditLossStatusDomain" xlink:label="loc_us-gaap_CreditLossStatusDomain_A522FE0E354F683107CD996F35AD1155" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditLossStatusAxis_110A28F297EDE2C5A099996F35ADBF54" xlink:to="loc_us-gaap_CreditLossStatusDomain_A522FE0E354F683107CD996F35AD1155" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember" xlink:label="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_90844FEC0A4FCA1B9528996F35AE7D90" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditLossStatusDomain_A522FE0E354F683107CD996F35AD1155" xlink:to="loc_us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_90844FEC0A4FCA1B9528996F35AE7D90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance_A092C62C47F03D42CB26996F35AE83C0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance_A092C62C47F03D42CB26996F35AE83C0" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesPurchaseDiscount" xlink:label="loc_smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesPurchaseDiscount_DE55894E3E6BA433C8EC996F35AFF66A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesPurchaseDiscount_DE55894E3E6BA433C8EC996F35AFF66A" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNetOfPurchaseDiscount" xlink:label="loc_smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNetOfPurchaseDiscount_55B821EDFA76CBE75673996F35AF34B7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_smbk_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNetOfPurchaseDiscount_55B821EDFA76CBE75673996F35AF34B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAllowanceForLoanLosses" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAllowanceForLoanLosses_ECC65807A474E6888E25996F35AF52A1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAllowanceForLoanLosses_ECC65807A474E6888E25996F35AF52A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet" xlink:label="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet_F68B810C2B001A134955996F35AF91D3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodLineItems_17326BA3C85816697D2C996F35AE33F2" xlink:to="loc_us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet_F68B810C2B001A134955996F35AF91D3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/LoansAndAllowanceForLoanLossesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/PresentationOfFinancialInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/PresentationOfFinancialInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_3D531E829DD935462A438DDCDF310E4A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_E31D2AC74A37DF907A198DDCDF2FFD31" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_3D531E829DD935462A438DDCDF310E4A" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_E31D2AC74A37DF907A198DDCDF2FFD31" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_C4116826BCDBF6DD1A2F8DDCDF30C607" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_E31D2AC74A37DF907A198DDCDF2FFD31" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_C4116826BCDBF6DD1A2F8DDCDF30C607" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_D91FDEA4F65AABA9EECB8DDCDF3067CE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_C4116826BCDBF6DD1A2F8DDCDF30C607" xlink:to="loc_us-gaap_TypeOfAdoptionMember_D91FDEA4F65AABA9EECB8DDCDF3067CE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_D91FDEA4F65AABA9EECB8DDCDF3067CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_C4116826BCDBF6DD1A2F8DDCDF30C607" xlink:to="loc_us-gaap_TypeOfAdoptionMember_D91FDEA4F65AABA9EECB8DDCDF3067CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_EBE82D23E69973AF63178DDCDF30FC0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_D91FDEA4F65AABA9EECB8DDCDF3067CE" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_EBE82D23E69973AF63178DDCDF30FC0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_60F2C424A8FA75CFFA568DDCDF315129" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_3D531E829DD935462A438DDCDF310E4A" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_60F2C424A8FA75CFFA568DDCDF315129" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_A2DA47E57F76251B97DC8DDCDF31C806" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_3D531E829DD935462A438DDCDF310E4A" xlink:to="loc_us-gaap_OperatingLeaseLiability_A2DA47E57F76251B97DC8DDCDF31C806" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/PresentationOfFinancialInformationPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/Securities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SecuritiesAmortizedCostAndFairValueOfAvailableForSaleSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_B86738DD41D689BA6EA4555311D677ED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_B86738DD41D689BA6EA4555311D677ED" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_696794D3D93422A851BF555311D65DFB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_B86738DD41D689BA6EA4555311D677ED" xlink:to="loc_us-gaap_FinancialInstrumentAxis_696794D3D93422A851BF555311D65DFB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_696794D3D93422A851BF555311D65DFB" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_696794D3D93422A851BF555311D65DFB" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_B83FD344318F0B74CBC9555311D72F53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_B83FD344318F0B74CBC9555311D72F53" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_MunicipalSecuritiesMember" xlink:label="loc_smbk_MunicipalSecuritiesMember_5F1E7EF3AE94C134DCEE555311D7D701" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:to="loc_smbk_MunicipalSecuritiesMember_5F1E7EF3AE94C134DCEE555311D7D701" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherDebtSecuritiesMember" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_C2F89F62DCFFEA9EFAF5555311D7CEF6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_C2F89F62DCFFEA9EFAF5555311D7CEF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_6590E67EF0F942314F17555311D72B2E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CB7D1886A814C4157761555311D7EC45" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_6590E67EF0F942314F17555311D72B2E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_3CB6FD1CCE70EBF7D983555311D8CBF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_3CB6FD1CCE70EBF7D983555311D8CBF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_54CF03A1AA75F13207FF555311D8C780" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_54CF03A1AA75F13207FF555311D8C780" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_73E8FCB229062ED47D76555311D887E7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_73E8FCB229062ED47D76555311D887E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_795F4A926D25A8239690555311D81187" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7924251843C83B2DC40D555311D826AA" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_795F4A926D25A8239690555311D81187" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SecuritiesAvailableForSaleSecuritiesByContractualMaturityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1FB77B9D6B95A7B278588DF642A54EEF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1FB77B9D6B95A7B278588DF642A54EEF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_03D75F88CABDD872EC638DF642A51F48" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1FB77B9D6B95A7B278588DF642A54EEF" xlink:to="loc_us-gaap_FinancialInstrumentAxis_03D75F88CABDD872EC638DF642A51F48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_D0077F2F0FD1C2E550328DF642A6FB6A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_03D75F88CABDD872EC638DF642A51F48" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_D0077F2F0FD1C2E550328DF642A6FB6A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_D0077F2F0FD1C2E550328DF642A6FB6A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_03D75F88CABDD872EC638DF642A51F48" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_D0077F2F0FD1C2E550328DF642A6FB6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBackedSecuritiesMember" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_72F7E7930C8ACBC414688DF642A6268F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_D0077F2F0FD1C2E550328DF642A6FB6A" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_72F7E7930C8ACBC414688DF642A6268F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_2BAF45E4AF3BC88124578DF642A6D39F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_2BAF45E4AF3BC88124578DF642A6D39F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_F41A3672E2A46FDA61538DF642A78A62" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_F41A3672E2A46FDA61538DF642A78A62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_0F070E4C30CAF705BFFF8DF642A7CFBD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_0F070E4C30CAF705BFFF8DF642A7CFBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_5BB8AC267BCD3ADF560E8DF642A7C283" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_5BB8AC267BCD3ADF560E8DF642A7C283" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_CED39866C9C888F34EC38DFBE47D6411" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_CED39866C9C888F34EC38DFBE47D6411" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_A975BB02376EC2AA19CF8DF642A7F2E3" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_A975BB02376EC2AA19CF8DF642A7F2E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_51194D43A0E339E66C908DF642A712C4" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_51194D43A0E339E66C908DF642A712C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_D432A2A201B06A5E51988DF642A7702C" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_D432A2A201B06A5E51988DF642A7702C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_D84D21E1C23D737CEF2F8DF642A8DCA0" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_D84D21E1C23D737CEF2F8DF642A8DCA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_38B8D6101A7CB57C762D8DF642A83BA1" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_38B8D6101A7CB57C762D8DF642A83BA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_CE509C281A921ABC40968DF642A85497" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_CE509C281A921ABC40968DF642A85497" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_B5B02B3A5A44ED5BB2D08E121D3A5DF0" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_B5B02B3A5A44ED5BB2D08E121D3A5DF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_33FFD0944C03A9BF647B8DF642A84000" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_33FFD0944C03A9BF647B8DF642A84000" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_CF45F5BDE26F7C804CDA8DF642A8FCC9" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_E55BF1D1081D52481B258DF642A6C828" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_CF45F5BDE26F7C804CDA8DF642A8FCC9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SecuritiesAvailableForSaleSecuritiesInContinuousLossPositionDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_2AC9CB48546D55D2A766EDB89CD28C0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_2AC9CB48546D55D2A766EDB89CD28C0C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_88C9D2ADDBF55355BDAC1640FCE849DE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_2AC9CB48546D55D2A766EDB89CD28C0C" xlink:to="loc_us-gaap_FinancialInstrumentAxis_88C9D2ADDBF55355BDAC1640FCE849DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04B5FE3F3B89F2F30450C10A83147520_6E92EEDC0CE25D2F91F96A0D227667E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_88C9D2ADDBF55355BDAC1640FCE849DE" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04B5FE3F3B89F2F30450C10A83147520_6E92EEDC0CE25D2F91F96A0D227667E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_88C9D2ADDBF55355BDAC1640FCE849DE" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_6DB3C61022E9535D9A62BC863F260B39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_6DB3C61022E9535D9A62BC863F260B39" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_MunicipalSecuritiesMember" xlink:label="loc_smbk_MunicipalSecuritiesMember_E15B643226E658E7AF46925B905C16FA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:to="loc_smbk_MunicipalSecuritiesMember_E15B643226E658E7AF46925B905C16FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherDebtSecuritiesMember" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_C9C251320E4C50198709E15D9613F21A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_C9C251320E4C50198709E15D9613F21A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_CBF63489C9A354CDB705B1C449AF7B73" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_EBF6C596F16A523295B0C12C5A9B51CF" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_CBF63489C9A354CDB705B1C449AF7B73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_B6204D95A43C5E6298ADCC53D5CC2379" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_B6204D95A43C5E6298ADCC53D5CC2379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_250778F96EA35614983BC11153A169BC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_250778F96EA35614983BC11153A169BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_435F81DEBF8E59FEAB5077BE49A45B6A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_435F81DEBF8E59FEAB5077BE49A45B6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_46FF8211D9595B688513E9EB3F31B7B1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_46FF8211D9595B688513E9EB3F31B7B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_89A4C189FD365252AB3393B797E1403C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_89A4C189FD365252AB3393B797E1403C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_23AB8BA969AD50FFBDA4BD085BAD7E7D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_C2CC06850586520BA5F83D5E2ADEC963" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_23AB8BA969AD50FFBDA4BD085BAD7E7D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SecuritiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureLineItems" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableDisclosureTable" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_A6E6F46C33AE3DEBEB3855CB0D98C20D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_A6E6F46C33AE3DEBEB3855CB0D98C20D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_ABFF7F2CFD504039EF8C55CB0D9A922E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_A6E6F46C33AE3DEBEB3855CB0D98C20D" xlink:to="loc_us-gaap_FinancialInstrumentAxis_ABFF7F2CFD504039EF8C55CB0D9A922E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_ABFF7F2CFD504039EF8C55CB0D9A922E" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_ABFF7F2CFD504039EF8C55CB0D9A922E" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_FA97B72C9D568B58112355CB0D9AAE6F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_FA97B72C9D568B58112355CB0D9AAE6F" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_MunicipalSecuritiesMember" xlink:label="loc_smbk_MunicipalSecuritiesMember_5D024C469ADC7B01D0F855CB0D9B7F9A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:to="loc_smbk_MunicipalSecuritiesMember_5D024C469ADC7B01D0F855CB0D9B7F9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherDebtSecuritiesMember" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_2C272217E96B04E3269E55CB0D9B9166" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_2C272217E96B04E3269E55CB0D9B9166" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_E9E0CF2DFC6CE801A80855CB0D9BAE0E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_C1B7969A37E8DAA49FEA55CB0D9A4E19" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_E9E0CF2DFC6CE801A80855CB0D9BAE0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralAxis" xlink:label="loc_us-gaap_CollateralAxis_808627A7A1B35A25F08255CB0D9B0AFD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureTable_A6E6F46C33AE3DEBEB3855CB0D98C20D" xlink:to="loc_us-gaap_CollateralAxis_808627A7A1B35A25F08255CB0D9B0AFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_7B30A7ED651BA9C5813655CB0D9CCA33_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_808627A7A1B35A25F08255CB0D9B0AFD" xlink:to="loc_us-gaap_CollateralDomain_7B30A7ED651BA9C5813655CB0D9CCA33_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_7B30A7ED651BA9C5813655CB0D9CCA33" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_808627A7A1B35A25F08255CB0D9B0AFD" xlink:to="loc_us-gaap_CollateralDomain_7B30A7ED651BA9C5813655CB0D9CCA33" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralPledgedMember" xlink:label="loc_us-gaap_CollateralPledgedMember_92488D432A82CEACC55755CB0D9C49C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_7B30A7ED651BA9C5813655CB0D9CCA33" xlink:to="loc_us-gaap_CollateralPledgedMember_92488D432A82CEACC55755CB0D9C49C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRestricted" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_1394CD7C7D5BA97AE62655CB0D9CE5C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_1394CD7C7D5BA97AE62655CB0D9CE5C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_C546AF3F1E8089083A4B55CB0D9D66D6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_C546AF3F1E8089083A4B55CB0D9D66D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_086D0CAC38415A31ABDB55CB0D9DBBD2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_086D0CAC38415A31ABDB55CB0D9DBBD2" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_ProceedsFromCallsOfDebtSecuritiesAvailableForSale" xlink:label="loc_smbk_ProceedsFromCallsOfDebtSecuritiesAvailableForSale_72B4ED25D5F631A8EEFC55CD500CF564" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_smbk_ProceedsFromCallsOfDebtSecuritiesAvailableForSale_72B4ED25D5F631A8EEFC55CD500CF564" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_ABDE246E6241073B884755CB0D9D5C76" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoansAndLeasesReceivableDisclosureLineItems_BF73D316E6455E0CD70C55CB0D9CBF36" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_ABDE246E6241073B884755CB0D9D5C76" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SecuritiesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SubsequentEvents" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.smartbank.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_AFB47A2BCB74DC49EB297A41E82170B5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_7C57DC31FE8BCED2C40D7A41E81FEA99" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_AFB47A2BCB74DC49EB297A41E82170B5" xlink:to="loc_us-gaap_SubsequentEventTable_7C57DC31FE8BCED2C40D7A41E81FEA99" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_00ED1EFFC6919452C6667A41E8202D84" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_7C57DC31FE8BCED2C40D7A41E81FEA99" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_00ED1EFFC6919452C6667A41E8202D84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_1F61FEB04337DBAFD9E47A41E820796E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_00ED1EFFC6919452C6667A41E8202D84" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_1F61FEB04337DBAFD9E47A41E820796E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_1F61FEB04337DBAFD9E47A41E820796E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_00ED1EFFC6919452C6667A41E8202D84" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_1F61FEB04337DBAFD9E47A41E820796E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_EFE69F6EA5E99FDAA02A7A41E820BA71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_1F61FEB04337DBAFD9E47A41E820796E" xlink:to="loc_us-gaap_SubsequentEventMember_EFE69F6EA5E99FDAA02A7A41E820BA71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01C921CFFEFADCD731C67A41E820477F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_7C57DC31FE8BCED2C40D7A41E81FEA99" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01C921CFFEFADCD731C67A41E820477F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_530FD41C49346F0AFF2C7A41E8213BC7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01C921CFFEFADCD731C67A41E820477F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_530FD41C49346F0AFF2C7A41E8213BC7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_530FD41C49346F0AFF2C7A41E8213BC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01C921CFFEFADCD731C67A41E820477F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_530FD41C49346F0AFF2C7A41E8213BC7" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_EntegraFinancialCorpMember" xlink:label="loc_smbk_EntegraFinancialCorpMember_923DC6A41B9BEED597B77A6E0C7168B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_530FD41C49346F0AFF2C7A41E8213BC7" xlink:to="loc_smbk_EntegraFinancialCorpMember_923DC6A41B9BEED597B77A6E0C7168B7" xlink:type="arc" />
    <link:loc xlink:href="smbk-20190331.xsd#smbk_BusinessCombinationTerminationFeeReceived" xlink:label="loc_smbk_BusinessCombinationTerminationFeeReceived_3E0F5CABFD8F35F0D5BD7A6EB8F8F3F1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_AFB47A2BCB74DC49EB297A41E82170B5" xlink:to="loc_smbk_BusinessCombinationTerminationFeeReceived_3E0F5CABFD8F35F0D5BD7A6EB8F8F3F1" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
