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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-03-07</periodOfReport>

    <issuer>
        <issuerCik>0001472787</issuerCik>
        <issuerName>First American Financial Corp</issuerName>
        <issuerTradingSymbol>FAF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001243867</rptOwnerCik>
            <rptOwnerName>GILMORE DENNIS J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1 FIRST AMERICAN WAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA ANA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92707</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-03-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7459</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.96</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>613254</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2126.521</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 401(k) Plan Trust</value>
                    <footnoteId id="F8"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.25</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2002-12-13</value>
                <footnoteId id="F9"/>
            </exerciseDate>
            <expirationDate>
                <value>2011-12-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>18632</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18632</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.21</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2003-07-23</value>
                <footnoteId id="F10"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-07-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13974</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13974</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9.82</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2004-02-27</value>
                <footnoteId id="F11"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>116452</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>116452</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.13</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-02-26</value>
                <footnoteId id="F12"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-02-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>116453</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>116453</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.70</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2006-02-28</value>
                <footnoteId id="F13"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-02-28</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>139744</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>139744</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.40</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2006-12-08</value>
                <footnoteId id="F14"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-12-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>139744</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>139744</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Payment of tax liability by withholding securities incident to the vesting of restricted stock units.</footnote>
        <footnote id="F2">Includes 16,071 unvested restricted stock units (&quot;RSUs&quot;) acquired in a pro rata distribution by The First American Corporation (&quot;FAC&quot;) on account of an original grant of 30,948 FAC RSUs, of which 13,590 were unvested at the time of the distribution and shares acquired through automatic dividend reinvestment. The vesting schedule of the FAC RSUs, vesting in five equal annual increments commencing 3/5/08, the first anniversary of the grant, has been carried over to the issuer RSUs.</footnote>
        <footnote id="F3">Includes 38,442 unvested RSUs acquired in a pro rata distribution by FAC on account of an original grant of 37,878 FAC RSUs, of which 24,424 were unvested at the time of the distribution and shares acquired through automatic dividend reinvestment. The vesting schedule of the FAC RSUs, vesting in five equal annual increments commencing 3/4/09, the first anniversary of the grant, has been carried over to the issuer RSUs.</footnote>
        <footnote id="F4">Includes 58,008 unvested RSUs acquired in a pro rata distribution by FAC on account of an original grant of 39,504 FAC RSUs, of which 32,784 were unvested at the time of the distribution and shares acquired through automatic dividend reinvestment. The vesting schedule of the FAC RSUs, vesting in five equal annual increments commencing 3/4/10, the first anniversary of the grant, has been carried over to the issuer RSUs.</footnote>
        <footnote id="F5">Includes 109,247 unvested RSUs acquired in a pro rata distribution by FAC on account of an original grant of 57,551 FAC RSUs, of which 57,897 were unvested at the time of the distribution and shares acquired through automatic dividend reinvestment. The vesting schedule of the FAC RSUs, vesting in five equal annual increments commencing 3/3/11, the first anniversary of the grant, has been carried over to the issuer RSUs.</footnote>
        <footnote id="F6">Includes 215,453 shares acquired pursuant to a grant of performance based RSUs on account of an original grant of 212,765 RSUs and shares acquired through automatic dividend reinvestment, which vest (if the performance criteria have been met) in three equal annual increments commencing on 6/1/13, the third anniversary of the grant, pursuant to the Form of RSU Award Agreement filed as Exhibit 10(i) to the issuer's Quarterly Report on Form 10-Q for the period ended June 30, 2010.</footnote>
        <footnote id="F7">Includes 93,498 shares acquired pursuant to a grant of RSUs vesting in four equal increments commencing 3/3/12, the first anniversary of the grant.</footnote>
        <footnote id="F8">Amount shown consists of shares contributed by issuer as company match, shares purchased for the reporting person's account and shares acquired through automatic reinvestment of dividends paid as reported in most recent account statement in transactions exempt under rules 16a-3(f)(1)(i)(B) and 16b-3(c).</footnote>
        <footnote id="F9">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 12/13/02, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
        <footnote id="F10">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 7/23/03, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
        <footnote id="F11">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 2/27/04, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
        <footnote id="F12">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 2/26/05, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
        <footnote id="F13">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 2/28/06, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
        <footnote id="F14">The vesting schedule of the original FAC option, vesting in five equal annual increments commencing 12/8/06, the first anniversary of the grant, has been carried over to the issuer options.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Greg L. Smith, attorney-in-fact for Dennis J. Gilmore</signatureName>
        <signatureDate>2011-03-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
