<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2023 Workiva-->
<!--r:4d1efdb6-165c-4416-b4c2-e798beac0b95,g:919ec81e-0ff4-4d06-a265-7e55fe4e7f61-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.kforce.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="kfrc-20230630.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITY" xlink:type="extended" id="i36b8b1fdf4284a9bbf6160e91ea4c693_UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITY">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_c11de292-5cfe-4686-8859-870fd8823b25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c11de292-5cfe-4686-8859-870fd8823b25" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_c835a375-a267-41ed-aac1-1dc5e2d00295" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_c835a375-a267-41ed-aac1-1dc5e2d00295" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_f441ba58-2fb8-452e-adcb-c00dafb31ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockholdersEquity_f441ba58-2fb8-452e-adcb-c00dafb31ac6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_cbf10a42-9f34-4feb-b8b6-d097e23bc5c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_TreasuryStockCommonShares_cbf10a42-9f34-4feb-b8b6-d097e23bc5c6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_bd1390df-76ad-4854-ad1a-bf41248872c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_NetIncomeLoss_bd1390df-76ad-4854-ad1a-bf41248872c6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_c38e3585-78ef-4373-9261-9bfc4e37ff4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_c38e3585-78ef-4373-9261-9bfc4e37ff4a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_2e079894-2522-41c5-ba5c-c4b5cb26d12a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_2e079894-2522-41c5-ba5c-c4b5cb26d12a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3f8de199-5a08-4ed6-a491-099349d65206" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3f8de199-5a08-4ed6-a491-099349d65206" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_706ee26b-da0f-45af-9265-6e7afd8f64d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_706ee26b-da0f-45af-9265-6e7afd8f64d4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_d569028b-2b67-4054-92f3-2cfaf2a425f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_d569028b-2b67-4054-92f3-2cfaf2a425f2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_69a261b5-0920-446d-8602-6c805ca169b9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_DividendsCommonStock_69a261b5-0920-446d-8602-6c805ca169b9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_0846ed6b-b7c7-43c5-9a33-25cb7ebfcff7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_0846ed6b-b7c7-43c5-9a33-25cb7ebfcff7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_db042556-36ea-4f10-9cd8-517e765c3230" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_db042556-36ea-4f10-9cd8-517e765c3230" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_69ffbfaa-1401-4fbc-b4bf-3436f8379529" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_69ffbfaa-1401-4fbc-b4bf-3436f8379529" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_cfd1ff96-8102-4a87-9a26-37aee0a1b5cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_af336022-9337-467c-a5c8-39ec8148bdd3" xlink:to="loc_us-gaap_StockholdersEquityOther_cfd1ff96-8102-4a87-9a26-37aee0a1b5cf" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_9174549b-23c6-4337-80b0-6d8c1497cfd9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_5ad29105-bda0-4aab-958d-2f95128c9e74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_15fd9c81-2a56-4526-a00f-1900247ffbe6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_e9d169b8-5897-4677-8770-3208467f6383" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_c11de292-5cfe-4686-8859-870fd8823b25" xlink:to="loc_us-gaap_StatementTable_e9d169b8-5897-4677-8770-3208467f6383" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_fbc84670-dfba-448b-a8b4-8c2715df2f46" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_e9d169b8-5897-4677-8770-3208467f6383" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_fbc84670-dfba-448b-a8b4-8c2715df2f46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_fbc84670-dfba-448b-a8b4-8c2715df2f46_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fbc84670-dfba-448b-a8b4-8c2715df2f46" xlink:to="loc_us-gaap_EquityComponentDomain_fbc84670-dfba-448b-a8b4-8c2715df2f46_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fbc84670-dfba-448b-a8b4-8c2715df2f46" xlink:to="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_10099708-c569-4931-816c-6bec506588ec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:to="loc_us-gaap_CommonStockMember_10099708-c569-4931-816c-6bec506588ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_20473fcd-d27e-44c7-a3eb-02d96c49e822" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_20473fcd-d27e-44c7-a3eb-02d96c49e822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_7eb18a97-ed88-461f-97af-251843c71abb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_7eb18a97-ed88-461f-97af-251843c71abb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_324944c9-0558-4e81-bc44-681e99ee2378" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:to="loc_us-gaap_RetainedEarningsMember_324944c9-0558-4e81-bc44-681e99ee2378" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_4bdb9267-5a9c-468c-9659-0581a232a50d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ee21f4ce-5dd6-46d5-8fe9-1f8d3ee80766" xlink:to="loc_us-gaap_TreasuryStockCommonMember_4bdb9267-5a9c-468c-9659-0581a232a50d" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/SummaryofSignificantAccountingPoliciesEquityMethodInvestmentDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#SummaryofSignificantAccountingPoliciesEquityMethodInvestmentDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/SummaryofSignificantAccountingPoliciesEquityMethodInvestmentDetails" xlink:type="extended" id="i07c4d6c153ee471eb6a66a9c754c01af_SummaryofSignificantAccountingPoliciesEquityMethodInvestmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_08cf33f8-1afb-47fa-ad7e-bba29d2a8f2a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_08cf33f8-1afb-47fa-ad7e-bba29d2a8f2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_a34e1280-a499-485e-ab64-55281d62437e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_a34e1280-a499-485e-ab64-55281d62437e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_52e071d1-ae22-4283-82de-8ca787116c95" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_52e071d1-ae22-4283-82de-8ca787116c95" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_ReserveRelatedToNoteReceivable_9d19a92f-6b6d-4cb2-b8bb-4e00f204de53" xlink:href="kfrc-20230630.xsd#kfrc_ReserveRelatedToNoteReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_kfrc_ReserveRelatedToNoteReceivable_9d19a92f-6b6d-4cb2-b8bb-4e00f204de53" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableGrossNoncurrent_2e8319fb-3d23-440b-a3f7-facc635b3b67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesAndLoansReceivableGrossNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_NotesAndLoansReceivableGrossNoncurrent_2e8319fb-3d23-440b-a3f7-facc635b3b67" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_7597cf40-4b1e-4ffe-88dd-4e250bd54bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_7597cf40-4b1e-4ffe-88dd-4e250bd54bd5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_b7146938-33f6-4c7e-8da5-479d796ecf14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_b7146938-33f6-4c7e-8da5-479d796ecf14" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_ProceedsFromSaleOfEquityMethodInvestmentsNetOfTransactionCosts_a4b1fb62-f4be-42fe-86b5-8eecf92bc6c4" xlink:href="kfrc-20230630.xsd#kfrc_ProceedsFromSaleOfEquityMethodInvestmentsNetOfTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_kfrc_ProceedsFromSaleOfEquityMethodInvestmentsNetOfTransactionCosts_a4b1fb62-f4be-42fe-86b5-8eecf92bc6c4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_b55a95ba-28d2-4033-9a25-1f1e9758fe4e" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_775f0c0d-c1d4-4203-9be0-36349a39f646" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_775f0c0d-c1d4-4203-9be0-36349a39f646" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_775f0c0d-c1d4-4203-9be0-36349a39f646_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_775f0c0d-c1d4-4203-9be0-36349a39f646" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_775f0c0d-c1d4-4203-9be0-36349a39f646_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_314686d2-b9c9-434a-92e7-910b8d98c064" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_775f0c0d-c1d4-4203-9be0-36349a39f646" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_314686d2-b9c9-434a-92e7-910b8d98c064" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_WorkLLamaLLCMember_1e9f845b-d3f9-44f7-8d81-34a4ecf10862" xlink:href="kfrc-20230630.xsd#kfrc_WorkLLamaLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_314686d2-b9c9-434a-92e7-910b8d98c064" xlink:to="loc_kfrc_WorkLLamaLLCMember_1e9f845b-d3f9-44f7-8d81-34a4ecf10862" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_b053c444-bab7-4f48-a5a8-31a529b0df2f" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:to="loc_dei_LegalEntityAxis_b053c444-bab7-4f48-a5a8-31a529b0df2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b053c444-bab7-4f48-a5a8-31a529b0df2f_default" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_b053c444-bab7-4f48-a5a8-31a529b0df2f" xlink:to="loc_dei_EntityDomain_b053c444-bab7-4f48-a5a8-31a529b0df2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_cd72910d-46ad-44b9-b4d7-2c05996caf81" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_b053c444-bab7-4f48-a5a8-31a529b0df2f" xlink:to="loc_dei_EntityDomain_cd72910d-46ad-44b9-b4d7-2c05996caf81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_WorkLLamaLLCMember_d97324ae-ffef-44ac-96eb-da6673e353dd" xlink:href="kfrc-20230630.xsd#kfrc_WorkLLamaLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_cd72910d-46ad-44b9-b4d7-2c05996caf81" xlink:to="loc_kfrc_WorkLLamaLLCMember_d97324ae-ffef-44ac-96eb-da6673e353dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_93ebd757-0680-481e-afd9-6d4b9cab7851" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_93ebd757-0680-481e-afd9-6d4b9cab7851" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_93ebd757-0680-481e-afd9-6d4b9cab7851_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_93ebd757-0680-481e-afd9-6d4b9cab7851" xlink:to="loc_us-gaap_ReceivableTypeDomain_93ebd757-0680-481e-afd9-6d4b9cab7851_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_cc50444b-6b2c-4509-bffd-7ed83eb6dc32" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_93ebd757-0680-481e-afd9-6d4b9cab7851" xlink:to="loc_us-gaap_ReceivableTypeDomain_cc50444b-6b2c-4509-bffd-7ed83eb6dc32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableMember_2389e84d-3dfd-403b-8298-ea16ea45851a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_cc50444b-6b2c-4509-bffd-7ed83eb6dc32" xlink:to="loc_us-gaap_NotesReceivableMember_2389e84d-3dfd-403b-8298-ea16ea45851a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_e19d287c-11b5-45c8-9520-5132a60de4cf" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_576be541-6b8b-4b5b-8e98-82c59add9004" xlink:to="loc_srt_OwnershipAxis_e19d287c-11b5-45c8-9520-5132a60de4cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_e19d287c-11b5-45c8-9520-5132a60de4cf_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_e19d287c-11b5-45c8-9520-5132a60de4cf" xlink:to="loc_srt_OwnershipDomain_e19d287c-11b5-45c8-9520-5132a60de4cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_ca43641b-45d4-451f-89a1-d8921b466f34" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_e19d287c-11b5-45c8-9520-5132a60de4cf" xlink:to="loc_srt_OwnershipDomain_ca43641b-45d4-451f-89a1-d8921b466f34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_WorkLLamaLLCMember_277a23fa-4e8a-425e-afb4-9d68c77e08fb" xlink:href="kfrc-20230630.xsd#kfrc_WorkLLamaLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_ca43641b-45d4-451f-89a1-d8921b466f34" xlink:to="loc_kfrc_WorkLLamaLLCMember_277a23fa-4e8a-425e-afb4-9d68c77e08fb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/ReportableSegmentsDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#ReportableSegmentsDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/ReportableSegmentsDetails" xlink:type="extended" id="i82c0b17b9a5d4a46a47de202b4ac93a8_ReportableSegmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_931d266c-0489-428b-b075-bcd86c2860a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_931d266c-0489-428b-b075-bcd86c2860a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_1d79648d-9cd1-43d6-8c68-35567978fe26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:to="loc_us-gaap_GrossProfit_1d79648d-9cd1-43d6-8c68-35567978fe26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_e94d2f74-9a72-4123-ac8e-eb70e7f11cf9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:to="loc_us-gaap_OperatingExpenses_e94d2f74-9a72-4123-ac8e-eb70e7f11cf9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_fae6da56-a58c-4398-860b-f34046d4362e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_fae6da56-a58c-4398-860b-f34046d4362e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0bcc76f3-3b95-444d-a95e-f39db1ecb561" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1545b69b-63fc-450e-8758-6e6bdd471405" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0bcc76f3-3b95-444d-a95e-f39db1ecb561" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_416ec736-e74c-4893-82b6-3e8fc5b2d58c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0bcc76f3-3b95-444d-a95e-f39db1ecb561" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_416ec736-e74c-4893-82b6-3e8fc5b2d58c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_416ec736-e74c-4893-82b6-3e8fc5b2d58c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_416ec736-e74c-4893-82b6-3e8fc5b2d58c" xlink:to="loc_us-gaap_SegmentDomain_416ec736-e74c-4893-82b6-3e8fc5b2d58c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_df064526-6c35-46b1-af5e-8be5b9d14f8c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_416ec736-e74c-4893-82b6-3e8fc5b2d58c" xlink:to="loc_us-gaap_SegmentDomain_df064526-6c35-46b1-af5e-8be5b9d14f8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_TechnologySegmentMember_8f4a481a-85bc-4902-b3ea-65bc60625158" xlink:href="kfrc-20230630.xsd#kfrc_TechnologySegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_df064526-6c35-46b1-af5e-8be5b9d14f8c" xlink:to="loc_kfrc_TechnologySegmentMember_8f4a481a-85bc-4902-b3ea-65bc60625158" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_FinanceAndAccountingSegmentMember_8dff4ed1-d0d2-4884-9182-f6262a4f22d3" xlink:href="kfrc-20230630.xsd#kfrc_FinanceAndAccountingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_df064526-6c35-46b1-af5e-8be5b9d14f8c" xlink:to="loc_kfrc_FinanceAndAccountingSegmentMember_8dff4ed1-d0d2-4884-9182-f6262a4f22d3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/DisaggregationofRevenueDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#DisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/DisaggregationofRevenueDetails" xlink:type="extended" id="i9e8a90759f614045b5619ee7463fd1b2_DisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_952c85a2-e423-4715-b607-834d960941e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8b09744d-7a8d-4ea9-a99e-3ddea7b4c72f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_952c85a2-e423-4715-b607-834d960941e9" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8b09744d-7a8d-4ea9-a99e-3ddea7b4c72f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_880e3e22-1110-47d8-be75-b756278f2e93" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_952c85a2-e423-4715-b607-834d960941e9" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_880e3e22-1110-47d8-be75-b756278f2e93" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_880e3e22-1110-47d8-be75-b756278f2e93" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a" xlink:to="loc_us-gaap_SegmentDomain_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7f8090c7-980b-4564-bfd7-089293f09188" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_61e2e41d-8bcf-4f3b-b31b-2220d76a9e4a" xlink:to="loc_us-gaap_SegmentDomain_7f8090c7-980b-4564-bfd7-089293f09188" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_TechnologySegmentMember_62f059bd-51e5-41d2-b087-05a61e878e4b" xlink:href="kfrc-20230630.xsd#kfrc_TechnologySegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7f8090c7-980b-4564-bfd7-089293f09188" xlink:to="loc_kfrc_TechnologySegmentMember_62f059bd-51e5-41d2-b087-05a61e878e4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_FinanceAndAccountingSegmentMember_064d6ec2-fb03-4370-9722-b450ee3a9a04" xlink:href="kfrc-20230630.xsd#kfrc_FinanceAndAccountingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7f8090c7-980b-4564-bfd7-089293f09188" xlink:to="loc_kfrc_FinanceAndAccountingSegmentMember_064d6ec2-fb03-4370-9722-b450ee3a9a04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_880e3e22-1110-47d8-be75-b756278f2e93" xlink:to="loc_srt_ProductOrServiceAxis_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4" xlink:to="loc_srt_ProductsAndServicesDomain_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_2d1757da-0c7e-4195-a186-1dbe6dba5628" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_1f6707c1-a9e3-4b4b-a9d3-44338330c4f4" xlink:to="loc_srt_ProductsAndServicesDomain_2d1757da-0c7e-4195-a186-1dbe6dba5628" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_FlexRevenueMember_b8049503-be79-4dd7-80b0-7ff97377a0e8" xlink:href="kfrc-20230630.xsd#kfrc_FlexRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2d1757da-0c7e-4195-a186-1dbe6dba5628" xlink:to="loc_kfrc_FlexRevenueMember_b8049503-be79-4dd7-80b0-7ff97377a0e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_DirectHireRevenueMember_b7e21a8b-0959-4455-9826-32474af7062c" xlink:href="kfrc-20230630.xsd#kfrc_DirectHireRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2d1757da-0c7e-4195-a186-1dbe6dba5628" xlink:to="loc_kfrc_DirectHireRevenueMember_b7e21a8b-0959-4455-9826-32474af7062c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/CreditFacilityDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#CreditFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/CreditFacilityDetails" xlink:type="extended" id="i76849a8d0a724137b0189b2079f2003e_CreditFacilityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_5a198eb8-75e7-4da3-a9c1-7fdbe6c1a96a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_d61a7f3a-a6cc-4af4-8d66-82bfea53fcf7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_5a198eb8-75e7-4da3-a9c1-7fdbe6c1a96a" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_d61a7f3a-a6cc-4af4-8d66-82bfea53fcf7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_LineOfCreditAccordionFeatureIncreaseLimit_fba26128-b2f7-4260-b105-56a60f4c41cc" xlink:href="kfrc-20230630.xsd#kfrc_LineOfCreditAccordionFeatureIncreaseLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_5a198eb8-75e7-4da3-a9c1-7fdbe6c1a96a" xlink:to="loc_kfrc_LineOfCreditAccordionFeatureIncreaseLimit_fba26128-b2f7-4260-b105-56a60f4c41cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_07ada227-14a1-4948-b710-52565bced868" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_5a198eb8-75e7-4da3-a9c1-7fdbe6c1a96a" xlink:to="loc_us-gaap_LineOfCredit_07ada227-14a1-4948-b710-52565bced868" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_c68f74a6-31b0-476e-96a9-9e7f97ce5f9c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_5a198eb8-75e7-4da3-a9c1-7fdbe6c1a96a" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_c68f74a6-31b0-476e-96a9-9e7f97ce5f9c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_586bcd72-acbf-451e-8cd9-a72fc8edd90d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c68f74a6-31b0-476e-96a9-9e7f97ce5f9c" xlink:to="loc_us-gaap_DebtInstrumentAxis_586bcd72-acbf-451e-8cd9-a72fc8edd90d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_586bcd72-acbf-451e-8cd9-a72fc8edd90d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_586bcd72-acbf-451e-8cd9-a72fc8edd90d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_586bcd72-acbf-451e-8cd9-a72fc8edd90d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01e9f960-030e-4c24-943d-9a7c3ca7bcb9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_586bcd72-acbf-451e-8cd9-a72fc8edd90d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01e9f960-030e-4c24-943d-9a7c3ca7bcb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_CreditFacilityMember_8fe0deb6-9230-4ea6-a329-a8ee83cbcca9" xlink:href="kfrc-20230630.xsd#kfrc_CreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01e9f960-030e-4c24-943d-9a7c3ca7bcb9" xlink:to="loc_kfrc_CreditFacilityMember_8fe0deb6-9230-4ea6-a329-a8ee83cbcca9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_be9e818c-e01c-428d-b294-6bcdb63acffe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c68f74a6-31b0-476e-96a9-9e7f97ce5f9c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_be9e818c-e01c-428d-b294-6bcdb63acffe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_be9e818c-e01c-428d-b294-6bcdb63acffe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_be9e818c-e01c-428d-b294-6bcdb63acffe" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_be9e818c-e01c-428d-b294-6bcdb63acffe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0589b732-2e4f-4eb2-9df0-54cd5d745eda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_be9e818c-e01c-428d-b294-6bcdb63acffe" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0589b732-2e4f-4eb2-9df0-54cd5d745eda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_725925ad-0e93-435f-9ad7-abdf88829dba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_0589b732-2e4f-4eb2-9df0-54cd5d745eda" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_725925ad-0e93-435f-9ad7-abdf88829dba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_dd95265c-e333-4355-bba8-0a1e13eeeb2f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c68f74a6-31b0-476e-96a9-9e7f97ce5f9c" xlink:to="loc_us-gaap_CreditFacilityAxis_dd95265c-e333-4355-bba8-0a1e13eeeb2f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_dd95265c-e333-4355-bba8-0a1e13eeeb2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_dd95265c-e333-4355-bba8-0a1e13eeeb2f" xlink:to="loc_us-gaap_CreditFacilityDomain_dd95265c-e333-4355-bba8-0a1e13eeeb2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_726ada78-2a84-4983-9847-e7d715e45d11" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_dd95265c-e333-4355-bba8-0a1e13eeeb2f" xlink:to="loc_us-gaap_CreditFacilityDomain_726ada78-2a84-4983-9847-e7d715e45d11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_2123b294-aa83-4ba8-917b-b9aa993e2243" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_726ada78-2a84-4983-9847-e7d715e45d11" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_2123b294-aa83-4ba8-917b-b9aa993e2243" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/StockbasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#StockbasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/StockbasedCompensationNarrativeDetails" xlink:type="extended" id="i619b0c7576234aac92cbe6170795f788_StockbasedCompensationNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_12be4e81-8d68-4d08-8937-1fe27358d04f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_12be4e81-8d68-4d08-8937-1fe27358d04f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_ReductionOfSharesReservedForGrant_5ada22a9-742d-4a04-ba23-e8e0e1ddbfba" xlink:href="kfrc-20230630.xsd#kfrc_ReductionOfSharesReservedForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_kfrc_ReductionOfSharesReservedForGrant_5ada22a9-742d-4a04-ba23-e8e0e1ddbfba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_cb305307-4a36-4d47-8ebb-a3148aea9075" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_cb305307-4a36-4d47-8ebb-a3148aea9075" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e2cafdcb-04e3-404e-84b9-4ec0d51b184c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e2cafdcb-04e3-404e-84b9-4ec0d51b184c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_cd645b6f-7b71-4409-a4af-095601b2c5f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_cd645b6f-7b71-4409-a4af-095601b2c5f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40a6d3ec-1b96-4db9-b613-4c558573df53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_00bf4c1d-651a-435e-829d-6c9beee3e357" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40a6d3ec-1b96-4db9-b613-4c558573df53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_a3e36420-7216-4469-8556-0f1f214a9bb3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40a6d3ec-1b96-4db9-b613-4c558573df53" xlink:to="loc_us-gaap_PlanNameAxis_a3e36420-7216-4469-8556-0f1f214a9bb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_a3e36420-7216-4469-8556-0f1f214a9bb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_a3e36420-7216-4469-8556-0f1f214a9bb3" xlink:to="loc_us-gaap_PlanNameDomain_a3e36420-7216-4469-8556-0f1f214a9bb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2c92ccd1-26d1-44c4-bd4a-4c223c6c8425" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_a3e36420-7216-4469-8556-0f1f214a9bb3" xlink:to="loc_us-gaap_PlanNameDomain_2c92ccd1-26d1-44c4-bd4a-4c223c6c8425" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_TwoThousandTwentyThreeStockIncentivePlanMember_dd28d041-7529-468e-b69e-aba710af1806" xlink:href="kfrc-20230630.xsd#kfrc_TwoThousandTwentyThreeStockIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_2c92ccd1-26d1-44c4-bd4a-4c223c6c8425" xlink:to="loc_kfrc_TwoThousandTwentyThreeStockIncentivePlanMember_dd28d041-7529-468e-b69e-aba710af1806" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_19d8fe8c-dd89-4917-a2ec-db8abbd450bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40a6d3ec-1b96-4db9-b613-4c558573df53" xlink:to="loc_us-gaap_AwardTypeAxis_19d8fe8c-dd89-4917-a2ec-db8abbd450bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_19d8fe8c-dd89-4917-a2ec-db8abbd450bd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_19d8fe8c-dd89-4917-a2ec-db8abbd450bd" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_19d8fe8c-dd89-4917-a2ec-db8abbd450bd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ae24d8e-7a8a-45fd-9005-abf367caec05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_19d8fe8c-dd89-4917-a2ec-db8abbd450bd" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ae24d8e-7a8a-45fd-9005-abf367caec05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_OptionOrStockAppreciationRightMember_12a2e6f1-4445-4649-a60e-92c38ceb9593" xlink:href="kfrc-20230630.xsd#kfrc_OptionOrStockAppreciationRightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ae24d8e-7a8a-45fd-9005-abf367caec05" xlink:to="loc_kfrc_OptionOrStockAppreciationRightMember_12a2e6f1-4445-4649-a60e-92c38ceb9593" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_265175a3-e649-46c6-9e0e-5517a3bb26d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ae24d8e-7a8a-45fd-9005-abf367caec05" xlink:to="loc_us-gaap_CommonStockMember_265175a3-e649-46c6-9e0e-5517a3bb26d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_4e1cfded-721e-439c-a89d-f61a35fc4af5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ae24d8e-7a8a-45fd-9005-abf367caec05" xlink:to="loc_us-gaap_RestrictedStockMember_4e1cfded-721e-439c-a89d-f61a35fc4af5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/StockbasedCompensationSummaryofRestrictedStockActivityDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#StockbasedCompensationSummaryofRestrictedStockActivityDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/StockbasedCompensationSummaryofRestrictedStockActivityDetails" xlink:type="extended" id="i6c012714b5de4156a54ec70061ee3e32_StockbasedCompensationSummaryofRestrictedStockActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_82fc88af-5df3-4774-8a47-37328355fd2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_82fc88af-5df3-4774-8a47-37328355fd2c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_312d0338-e9c3-4ec7-a869-71d9b37aa4a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_312d0338-e9c3-4ec7-a869-71d9b37aa4a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2b7fdb8e-f8a9-4379-ab22-5779fce0b560" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2b7fdb8e-f8a9-4379-ab22-5779fce0b560" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_c45dea0e-8076-4567-9eee-635cedd9d547" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_c45dea0e-8076-4567-9eee-635cedd9d547" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_1e95d350-ceba-4da3-98b7-63d043039a81" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_34154f4a-02c2-4cbc-aafc-ef0af663c72e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_1e95d350-ceba-4da3-98b7-63d043039a81" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_30186923-446b-4a56-a500-8bd309efc87e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_82fc88af-5df3-4774-8a47-37328355fd2c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_d33b64a3-6e28-436b-8944-6487192c3e36" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_d33b64a3-6e28-436b-8944-6487192c3e36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_54de2b57-542b-4474-8ade-447b569f8464" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_54de2b57-542b-4474-8ade-447b569f8464" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_0d061e96-8788-4ab3-8574-6266a35fe371" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_0d061e96-8788-4ab3-8574-6266a35fe371" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_b08b111b-2be2-447e-a6f4-d2183395325f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_ab475c7e-ecfc-4d82-8a40-326442a89fae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_b08b111b-2be2-447e-a6f4-d2183395325f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_8766fe1e-1e8f-455d-9cc9-7a82de77889a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_a41253eb-bebe-4d34-b1b2-4f9218d535b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_82fc88af-5df3-4774-8a47-37328355fd2c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_a41253eb-bebe-4d34-b1b2-4f9218d535b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_0d2f88a7-5eb0-4e21-9329-8e4bf123c8e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_a41253eb-bebe-4d34-b1b2-4f9218d535b2" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_0d2f88a7-5eb0-4e21-9329-8e4bf123c8e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_65e496d1-b9f0-4210-9c4e-6536b9bc41f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_82fc88af-5df3-4774-8a47-37328355fd2c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_65e496d1-b9f0-4210-9c4e-6536b9bc41f6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_801e933e-762d-496f-aa47-9114e12b309c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_65e496d1-b9f0-4210-9c4e-6536b9bc41f6" xlink:to="loc_us-gaap_AwardTypeAxis_801e933e-762d-496f-aa47-9114e12b309c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_801e933e-762d-496f-aa47-9114e12b309c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_801e933e-762d-496f-aa47-9114e12b309c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_801e933e-762d-496f-aa47-9114e12b309c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ecf052d1-0c4c-4cf2-b92a-8e33b851577e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_801e933e-762d-496f-aa47-9114e12b309c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ecf052d1-0c4c-4cf2-b92a-8e33b851577e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_066b4283-5edd-4fe1-b02c-91322c88ed84" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ecf052d1-0c4c-4cf2-b92a-8e33b851577e" xlink:to="loc_us-gaap_RestrictedStockMember_066b4283-5edd-4fe1-b02c-91322c88ed84" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/DerivativeInstrumentandHedgingActivityNarrativeDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#DerivativeInstrumentandHedgingActivityNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/DerivativeInstrumentandHedgingActivityNarrativeDetails" xlink:type="extended" id="i2eb912bc830c4a1cae669681e2c76891_DerivativeInstrumentandHedgingActivityNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_a9c57e7e-efc6-4a93-9719-19d291ec8065" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgesLiabilities_f6c38c4a-d49d-4b5f-87ae-88f711daa18d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsAndHedgesLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_a9c57e7e-efc6-4a93-9719-19d291ec8065" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgesLiabilities_f6c38c4a-d49d-4b5f-87ae-88f711daa18d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_bbb0c51c-041e-4f9a-af72-f21855c9df98" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_a9c57e7e-efc6-4a93-9719-19d291ec8065" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_bbb0c51c-041e-4f9a-af72-f21855c9df98" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_f3a5c430-5491-42b3-89fa-0231b50a9d1e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_bbb0c51c-041e-4f9a-af72-f21855c9df98" xlink:to="loc_us-gaap_HedgingDesignationAxis_f3a5c430-5491-42b3-89fa-0231b50a9d1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_f3a5c430-5491-42b3-89fa-0231b50a9d1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_f3a5c430-5491-42b3-89fa-0231b50a9d1e" xlink:to="loc_us-gaap_HedgingDesignationDomain_f3a5c430-5491-42b3-89fa-0231b50a9d1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_91cce983-6694-4b15-910e-c2ec6f7f555e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_f3a5c430-5491-42b3-89fa-0231b50a9d1e" xlink:to="loc_us-gaap_HedgingDesignationDomain_91cce983-6694-4b15-910e-c2ec6f7f555e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_7df69581-8fd6-4172-93b2-2728c3f48e4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_91cce983-6694-4b15-910e-c2ec6f7f555e" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_7df69581-8fd6-4172-93b2-2728c3f48e4a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.kforce.com/role/DerivativeInstrumentandHedgingActivityAccumulatedDerivativeInstrumentGainLossActivityDetails" xlink:type="simple" xlink:href="kfrc-20230630.xsd#DerivativeInstrumentandHedgingActivityAccumulatedDerivativeInstrumentGainLossActivityDetails"/>
  <link:definitionLink xlink:role="http://www.kforce.com/role/DerivativeInstrumentandHedgingActivityAccumulatedDerivativeInstrumentGainLossActivityDetails" xlink:type="extended" id="i4a886acb55d44f3f92c486d8022bcd9e_DerivativeInstrumentandHedgingActivityAccumulatedDerivativeInstrumentGainLossActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_27ed1a6d-5f69-4957-a455-9416fb13b735" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_24e4291e-098c-4075-add8-e0929b5954fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_27ed1a6d-5f69-4957-a455-9416fb13b735" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_24e4291e-098c-4075-add8-e0929b5954fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_8ea9e9ef-3593-416c-97a5-4d010c24671f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_24e4291e-098c-4075-add8-e0929b5954fd" xlink:to="loc_us-gaap_StockholdersEquity_8ea9e9ef-3593-416c-97a5-4d010c24671f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_f88bdcdc-5c82-4b71-8fc1-cc9008f6a088" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_24e4291e-098c-4075-add8-e0929b5954fd" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_f88bdcdc-5c82-4b71-8fc1-cc9008f6a088" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_7215ac16-bdf1-4e95-a39f-ee58d9c47a2b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_218e11b0-10fd-4dd8-b0d6-4f76617ecc14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_27ed1a6d-5f69-4957-a455-9416fb13b735" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_218e11b0-10fd-4dd8-b0d6-4f76617ecc14" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_a50500b8-e4e3-4fd6-8292-0ed3038b4650" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_218e11b0-10fd-4dd8-b0d6-4f76617ecc14" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_a50500b8-e4e3-4fd6-8292-0ed3038b4650" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a50500b8-e4e3-4fd6-8292-0ed3038b4650_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a50500b8-e4e3-4fd6-8292-0ed3038b4650" xlink:to="loc_us-gaap_EquityComponentDomain_a50500b8-e4e3-4fd6-8292-0ed3038b4650_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_1119dec0-749a-4202-84d4-2f788cb72141" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a50500b8-e4e3-4fd6-8292-0ed3038b4650" xlink:to="loc_us-gaap_EquityComponentDomain_1119dec0-749a-4202-84d4-2f788cb72141" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_91657dca-7a7e-4da6-8f21-1851c1978a0e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1119dec0-749a-4202-84d4-2f788cb72141" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_91657dca-7a7e-4da6-8f21-1851c1978a0e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_kfrc_OptionOrStockAppreciationRightMember_34503571-3ca5-472a-aa2f-b6848b62d0a4" xlink:href="kfrc-20230630.xsd#kfrc_OptionOrStockAppreciationRightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kfrc_OptionOrStockAppreciationRightMember_34503571-3ca5-472a-aa2f-b6848b62d0a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_CommonStockMember" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockMember" xlink:type="arc" order="6"/>
  </link:definitionLink>
</link:linkbase>
