<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-03-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000722723</issuerCik>
        <issuerName>HANGER, INC.</issuerName>
        <issuerTradingSymbol>HGR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001456485</rptOwnerCik>
            <rptOwnerName>HAST REBECCA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1375 PICCARD DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>ROCKVILLE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20850</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President-Linkia, LLC</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-03-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3180</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26644</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-03-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>756</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25888</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a grant of time-based restricted stock under the Company's 2010 Omnibus Incentive Plan (the &quot;Plan&quot;), which vests to the extent of 25% annually on the first anniversary date of the grant and cumulatively vests to the extent of 25% each year thereafter.  The restricted stock being reported does not include the contingent right of the reporting person to receive up to 3,180 additional performance shares under the Plan based on the achievement of certain performance targets for the fiscal year 2015.</footnote>
        <footnote id="F2">Includes (i) unvested restricted shares totaling 3,180 shares of stock from an initial grant of 3,180 shares of restricted stock made on March 6, 2015; (ii) unvested restricted shares and fully vested shares totaling 2,407 shares of stock from an initial grant of 2,663 shares of restricted stock made on March 7, 2014; (iii) unvested restricted shares and fully vested shares totaling 2,985 shares of stock from an initial grant of 3,800 shares of restricted stock and performance shares made on March 11, 2013; (iv) unvested restricted shares totaling 2,100 shares of stock from an initial grant of 5,200 shares of restricted stock made on March 7, 2012; (v) unvested restricted shares totaling 2,600 shares of stock from an initial grant of 5,200 shares of restricted stock made on March 25, 2011; [continued in next footnote]</footnote>
        <footnote id="F3">(vi) unvested restricted shares and fully vested shares totaling 3,020 shares of stock from an initial grant of 7,500 shares of restricted stock made on March 30, 2010 and (vii) unvested restricted shares and fully vested shares from previous awards of restricted stock to the reporting person.  All remaining unvested restricted shares will continue to vest at a rate of 25% per year of the original grant amount on the anniversary date of the grant.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jessica Lochmann Allen, Attorney-in-Fact for Rebecca Hast</signatureName>
        <signatureDate>2015-03-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
