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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-04-15</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000895655</issuerCik>
        <issuerName>JARDEN CORP</issuerName>
        <issuerTradingSymbol>JAH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001644280</rptOwnerCik>
            <rptOwnerName>Hochfelder Peter A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1800 NORTH MILITARY TRAIL</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOCA RATON</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33431</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2016-04-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7319</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </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">Disposed of pursuant to the Agreement and Plan of Merger dated as of December 13, 2015 (the &quot;Merger Agreement&quot;) among the Issuer, Newell Rubbermaid Inc. (n/k/a Newell Brands Inc. and referred to herein as &quot;Newell&quot;), NCPF Acquisition Corp. I (&quot;Newell Merger Sub&quot;) and NCPF Acquisition Corp. II (&quot;Successor Merger Sub&quot;) pursuant to which Newell Merger Sub merged with and into the Issuer (the &quot;First Merger&quot;), with the Issuer continuing as the surviving corporation and as a wholly-owned subsidiary of Newell and, immediately following the effectiveness of the First Merger, the Issuer merged with and into Successor Merger Sub, with Successor Merger Sub continuing as the surviving corporation and as a direct wholly-owned subsidiary of Newell.</footnote>
        <footnote id="F2">Pursuant to the Merger Agreement, at the effective time of the First Merger, each share of Issuer common stock was converted into the right to receive a per share amount (the &quot;Merger Consideration&quot;) equal to (i) $21.00 in cash, without interest, and (ii) 0.862 of a share of Newell common stock. The disposition was exempt from Section 16(b) of the Securities Exchange Act of 1934, as amended, pursuant to Rule 16b-3 promulgated thereunder.</footnote>
        <footnote id="F3">Includes 3,769 restricted shares of the Issuer's common stock which, pursuant to the Merger Agreement, at the effective time of the First Merger, automatically vested and thereafter cancelled and converted into the right to receive the per share Merger Consideration (less any required withholding taxes) for each share of Issuer common stock underlying such restricted stock award.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/  Peter A. Hochfelder</signatureName>
        <signatureDate>2016-04-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
