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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-06-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000704051</issuerCik>
        <issuerName>LEGG MASON, INC.</issuerName>
        <issuerTradingSymbol>LM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000928265</rptOwnerCik>
            <rptOwnerName>PELTZ NELSON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>280 PARK AVE</rptOwnerStreet1>
            <rptOwnerStreet2>41ST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001345471</rptOwnerCik>
            <rptOwnerName>TRIAN FUND MANAGEMENT, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>280 PARK AVE</rptOwnerStreet1>
            <rptOwnerStreet2>41ST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-06-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4056</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3877774</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Please see explanation below</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents 2,028 shares of common stock granted to each of Messrs. Peltz and Garden pursuant to and under the conditions of the Legg Mason, Inc. Non-Employee Director Equity Plan, as amended. See Appendix A to the definitive proxy statement for Legg Mason Inc.'s 2013 Annual Meeting of Stockholders.  The shares of common stock, aggregating 4,056, were placed into an account of Trian Management (as defined in Note 2 below) for the benefit of the Trian Entities (as defined in Note 2 below) pursuant to an agreement between Trian Management and each of Messrs. Peltz and Garden, respectively, with respect to the fees received by each of them for serving on the Board of Directors of the Issuer.</footnote>
        <footnote id="F2">Trian Fund Management, L.P. (&quot;Trian Management&quot;) serves as the management company for Trian Partners, L.P., Trian Partners Master Fund, L.P., Trian Partners Parallel Fund I, L.P., Trian Partners Strategic Investment Fund-A, L.P., Trian Partners Strategic Investment Fund-N, L.P., Trian Partners Strategic Investment Fund-D, L.P., Trian Partners Fund (Sub)-G, L.P., Trian Partners Strategic Fund-G II, L.P., Trian Partners Strategic Fund G-III, L.P., Trian Partners Strategic Fund-K, L.P., and Trian Partners Strategic Fund-C, Ltd. (collectively, the &quot;Trian Entities&quot;) and as such determines the investment and voting decisions of the Trian Entities with respect to the shares of the Issuer held by them. Mr. Peltz is a member of Trian Fund Management GP, LLC, which is the general partner of Trian Management, and therefore is in a position to determine the investment and voting decisions made by Trian Management on its own behalf and on behalf of the Trian Entities.</footnote>
        <footnote id="F3">(FN 2, contd.) Accordingly, Mr. Peltz, may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 under the Securities Exchange Act of 1934) the shares beneficially owned by Trian Management and the Trian Entities and Trian Management may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 under the Securities Act of 1934) the shares beneficially owned by the Trian Entities. The Reporting Persons disclaim beneficial ownership of such shares except to the extent of their respective pecuniary interests therein and this report shall not be deemed an admission that the Reporting Persons are the beneficial owner of such securities for purposes of Section 16 or for any other purpose. Mr. Peltz is a director of the Issuer.</footnote>
    </footnotes>

    <remarks>The shares which are reported on this filing as being indirectly held by Nelson Peltz through his relationship with Trian Management and the Trian Entities and by Trian Management through its relationship with the Trian Entities, and the transaction with respect to such shares, are also reported on the filing on Form 4 made by Edward Garden and Trian Management, and represent the same shares and transaction.</remarks>

    <ownerSignature>
        <signatureName>Stuart I. Rosen, Attorney-In-Fact for Nelson Peltz</signatureName>
        <signatureDate>2019-06-24</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Stuart I. Rosen, Attorney-In-Fact for Nelson Peltz, member of the general partner of Trian Fund Management, L.P.</signatureName>
        <signatureDate>2019-06-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
