<SEC-DOCUMENT>0000893538-14-000061.txt : 20140812
<SEC-HEADER>0000893538-14-000061.hdr.sgml : 20140812
<ACCEPTANCE-DATETIME>20140811180026
ACCESSION NUMBER:		0000893538-14-000061
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140811
FILED AS OF DATE:		20140811
DATE AS OF CHANGE:		20140811

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SM Energy Co
		CENTRAL INDEX KEY:			0000893538
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				410518430
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1775 SHERMAN STREET
		STREET 2:		SUITE 1200
		CITY:			DENVER
		STATE:			CO
		ZIP:			80203
		BUSINESS PHONE:		303-861-8140

	MAIL ADDRESS:	
		STREET 1:		1775 SHERMAN STREET
		STREET 2:		SUITE 1200
		CITY:			DENVER
		STATE:			CO
		ZIP:			80203

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ST MARY LAND & EXPLORATION CO
		DATE OF NAME CHANGE:	19940228

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Leyendecker Gregory T
		CENTRAL INDEX KEY:			0001406892

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31539
		FILM NUMBER:		141032036

	MAIL ADDRESS:	
		STREET 1:		1776 LINCOLN ST.
		STREET 2:		STE. 700
		CITY:			DENVER
		STATE:			CO
		ZIP:			80203
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_140779441448536.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-08-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000893538</issuerCik>
        <issuerName>SM Energy Co</issuerName>
        <issuerTradingSymbol>SM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406892</rptOwnerCik>
            <rptOwnerName>Leyendecker Gregory T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1775 SHERMAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80203</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. VP &amp; Regional Manager</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-08-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1338</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1338.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1338</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of stock. The restricted stock unit grant vests in three equal annual installments beginning July 1, 2015. The vested shares will be issued to the reporting person on the vesting dates, at which time all restrictions on the vested shares will lapse.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Karin M. Writer (Attorney-In-Fact)</signatureName>
        <signatureDate>2014-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
