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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-01-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001713952</issuerCik>
        <issuerName>Vivint Smart Home, Inc.</issuerName>
        <issuerTradingSymbol>VVNT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001521955</rptOwnerCik>
            <rptOwnerName>Lindquist Shawn J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIVINT SMART HOME, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4931 NORTH 300 WEST</rptOwnerStreet2>
            <rptOwnerCity>PROVO</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84604</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Legal Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Earnout Rights</value>
            </securityTitle>
            <conversionOrExercisePrice>
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            <transactionDate>
                <value>2020-01-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>26724</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2025-01-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>26724</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26724</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Appreciation Rights</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.41</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-01-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>73452</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2028-06-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>73452</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>73452</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to an Agreement and Plan of Merger, dated effective as of September 15, 2019, as amended by that certain Amendment No. 1 and as otherwise amended from time to time (the &quot;Merger Agreement&quot;), by and among Legacy Vivint Smart Home, Inc. (f/k/a Vivint Smart Home, Inc.) (&quot;Legacy Vivint Smart Home&quot;), Mosaic Acquisition Corp. (&quot;Mosaic&quot;) and Maiden Merger Sub, Inc. (&quot;Merger Sub&quot;), Merger Sub merged (the &quot;Merger&quot;) with and into Legacy Vivint Smart Home, with Legacy Vivint Smart Home surviving the merger as a wholly owned subsidiary of Mosaic (which subsequently changed its name to &quot;Vivint Smart Home, Inc.&quot;, the &quot;Issuer&quot;).</footnote>
        <footnote id="F2">Pursuant to the terms of the Merger Agreement, the stockholders of Legacy Vivint Smart Home at the effective time of the Merger (the &quot;Effective Time&quot;) received 84.5320916792 shares of Class A common stock of the Issuer (&quot;Class A Common Stock&quot;) for each share of common stock of Legacy Vivint Smart Home held by them immediately prior to the Effective Time and certain rights to additional shares of Class A Common Stock upon the achievement of certain milestones as described in the Merger Agreement (the &quot;Earnout Rights&quot;).  Additionally, certain  equity awards of a subsidiary of Legacy Vivint Smart Home were canceled and converted into equity awards of the Issuer, and restricted shares of common stock of Legacy Vivint Smart Home, issued in respect of a redemption of certain Class B Units of 313 Acquisition LLC, were cancelled and converted into restricted shares of Class A Common Stock of the Issuer.</footnote>
        <footnote id="F3">Reflects Earnout Rights acquired pursuant to the Merger Agreement.  Pursuant to earnout provisions in the Merger Agreement, the Reporting Person is entitled to receive such shares of Class A Common Stock if, from the closing of the Merger until the fifth anniversary thereof, the volume-weighted average price of the Class A Common Stock exceeds certain thresholds as discussed below.</footnote>
        <footnote id="F4">Of these Earnout Rights, one-third will be issued if the volume-weighted average price of the Class A Common Stock exceeds $12.50 for any 20 trading days within any 30 trading day period, one-third will be issued if the volume-weighted average price of the Class A Common Stock exceeds $15.00 for any 20 trading days within any 30 trading day period, and one-third will be issued if the volume-weighted average price of the Class A Common Stock exceeds $17.50 for any 20 trading days within any 30 trading day period.  The issuance of such shares are subject to certain adjustments, including pro rata adjustments, set forth in the Merger Agreement.</footnote>
        <footnote id="F5">Reflects stock appreciation rights (&quot;SARs&quot;) issued pursuant to the Merger Agreement.  9,793 of these SARs are vested.  The unvested SARs vest as follows: (a) 39,175 vest in four equal annual installments beginning on June 12, 2020, and (b) 24,484 vest in four equal annual installments beginning on January 17, 2021, or in the case of (b), earlier if certain performance thresholds are achieved.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Shawn J. Lindquist</signatureName>
        <signatureDate>2020-01-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
