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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-09-04</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001102993</issuerCik>
        <issuerName>LIVEPERSON INC</issuerName>
        <issuerTradingSymbol>LPSN</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002023502</rptOwnerCik>
            <rptOwnerName>Lane Nathan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O LIVEPERSON, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>530 7TH AVE., FLOOR M1</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10018</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>23350</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On September 4, 2026, pursuant to the terms of the Amended and Restated Merger Agreement, dated as of July 2, 2026 (the &quot;Merger Agreement&quot;), by and among the Issuer, SoundHound AI, Inc., a Delaware corporation (the &quot;Parent&quot;), Lightspeed Merger Sub Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (&quot;Merger Sub&quot;), and Lightspeed Merger Sub II Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (&quot;Merger Sub II&quot;), Merger Sub merged with and into the Issuer and immediately thereafter, Merger Sub II merged with and into the Issuer, with the Issuer continuing as the surviving corporation as an indirect wholly owned subsidiary of Parent (the &quot;Mergers&quot;).</footnote>
        <footnote id="F2">Represents 23,350 restricted stock units previously awarded by the Issuer (&quot;Company RSUs&quot;) and held by the reporting person immediately prior to the First Effective Time (as defined in the Merger Agreement).</footnote>
        <footnote id="F3">Pursuant to the Merger Agreement, at the First Effective Time, these Company RSUs were cancelled and converted into the right to receive the Per Share Merger Consideration, subject to the terms and conditions of the Merger Agreement, in respect of each share of Issuer common stock subject to such Company RSU.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Monica L. Greenberg, Attorney-in-Fact for Nathan Lane</signatureName>
        <signatureDate>2026-09-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
