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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-11-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001498511</rptOwnerCik>
            <rptOwnerName>Morton Andrew C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10910 DOMAIN DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78758</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP - Human Resources</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-11-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>339</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.04</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>38380</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects payment of tax liability by withholding shares of stock incident to vesting of restricted stock previously issued.</footnote>
        <footnote id="F2">Includes (i) unvested restricted shares which total 5,000 shares of stock from an initial grant of 5,000 shares of restricted stock that begins to vest on October 11, 2017; (ii) unvested restricted shares totaling 8,000 shares of stock from an initial grant of 8,000 shares of restricted stock that begins to vest on March 7, 2017; (iii) unvested restricted shares and fully vested shares totaling 4,619 shares of stock from an initial grant of 4,958 shares of restricted stock made on November 10, 2015; (iv) unvested restricted shares and fully vested shares totaling 3,893 shares of stock from an initial grant of 4,239 shares of restricted stock made on March 6, 2015; (v) unvested restricted shares and fully vested shares totaling 1,726 shares of stock from an initial grant of 2,064 shares of restricted stock made on March 7, 2014; [continued in next footnote]</footnote>
        <footnote id="F3">(vi) unvested restricted shares and fully vested shares totaling 2,987 shares of stock from an initial grant of 3,958 shares of restricted stock and performance shares made on March 11, 2013; (vii) fully vested shares totaling 2,930 shares of stock from an initial grant of 5,000 shares of restricted stock made on March 7, 2012; (viii) fully vested shares totaling 3,060 shares of stock from an initial grant of 4,900 shares of restricted stock made on March 25, 2011; and (ix) fully vested shares totaling 6,165 shares of stock from an initial grant of 12,000 shares of restricted stock made on June 21, 2010.  Except as otherwise noted, 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>

    <ownerSignature>
        <signatureName>/s/ Jessica Lochmann Allen, Attorney-in-Fact for Andrew C. Morton</signatureName>
        <signatureDate>2016-11-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
