<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4/A</documentType>
<periodOfReport>2003-09-08</periodOfReport>
<dateOfOriginalSubmission>2003-09-09</dateOfOriginalSubmission>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000093859</issuerCik>
        <issuerName>STEAK &amp; SHAKE CO</issuerName>
        <issuerTradingSymbol>SNS</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001243550</rptOwnerCik>
            <rptOwnerName>KELLEY WAYNE L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3800 ARCO CORPORATE DR.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28273</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable>
<nonDerivativeHolding>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>405334</value>
<footnoteId id="F2"/>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Kelley &amp; Partners L.P.</value>
<footnoteId id="F3"/>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>66181</value>
<footnoteId id="F2"/>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Kelley &amp; Partners II</value>
<footnoteId id="F1"/>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
</nonDerivativeTable>
<footnotes>
<footnote id="F1">These shares are held by Kelley &amp; Partners II, transactions for which are reported by S. Sue Aramian.</footnote>
<footnote id="F2">The figures for Mr. Kelley&#039;s indirect holdings were erroneous on the Form 4 filed to report his September 8, 2003 sale of 2,000 shares he holds directly.  The figures for his indirect holdings set forth herein are correct.</footnote>
<footnote id="F3">These shares are held by Kelley &amp; Partners, L.P., in which Mr. Kelley is a General Partner.  The transactions for this entity are reported by S. Sue Aramian.</footnote>
</footnotes>
<remarks></remarks>
<ownerSignature>
<signatureName>David C. Milne; Attorney in fact</signatureName>
<signatureDate>2003-09-12</signatureDate>
</ownerSignature>
</ownershipDocument>

