<SEC-DOCUMENT>0000899243-21-006128.txt : 20210211
<SEC-HEADER>0000899243-21-006128.hdr.sgml : 20210211
<ACCEPTANCE-DATETIME>20210211213001
ACCESSION NUMBER:		0000899243-21-006128
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210209
FILED AS OF DATE:		20210211
DATE AS OF CHANGE:		20210211

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Brown Christopher
		CENTRAL INDEX KEY:			0001378842

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39675
		FILM NUMBER:		21622233

	MAIL ADDRESS:	
		STREET 1:		C/O OPTIUM CORPORATION
		STREET 2:		500 HORIZON DRIVE, SUITE 500
		CITY:			CHALFONT
		STATE:			PA
		ZIP:			18914

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLEGRO MICROSYSTEMS, INC.
		CENTRAL INDEX KEY:			0000866291
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				462405937
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		955 PERIMETER ROAD
		CITY:			MANCHESTER
		STATE:			NH
		ZIP:			03103
		BUSINESS PHONE:		(603) 626-2300

	MAIL ADDRESS:	
		STREET 1:		955 PERIMETER ROAD
		CITY:			MANCHESTER
		STATE:			NH
		ZIP:			03103

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGRO MICROSYSTEMS INC
		DATE OF NAME CHANGE:	19900730
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-02-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000866291</issuerCik>
        <issuerName>ALLEGRO MICROSYSTEMS, INC.</issuerName>
        <issuerTradingSymbol>ALGM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378842</rptOwnerCik>
            <rptOwnerName>Brown Christopher</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>955 PERIMETER ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MANCHESTER</rptOwnerCity>
            <rptOwnerState>NH</rptOwnerState>
            <rptOwnerZipCode>03103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>See Remarks</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-02-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>29.1638</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>185097</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks>SVP, General Counsel and Secretary</remarks>

    <ownerSignature>
        <signatureName>/s/ Christopher E. Brown</signatureName>
        <signatureDate>2021-02-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
