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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-12-17</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001871509</issuerCik>
        <issuerName>Portillo's Inc.</issuerName>
        <issuerTradingSymbol>PTLO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001517319</rptOwnerCik>
            <rptOwnerName>Dodson Paulette R.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PORTILLO'S INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2001 SPRING ROAD, SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>OAK BROOK</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60523</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks>Exhibit 24 - Power of Attorney (incorporated herein by reference).</remarks>

    <ownerSignature>
        <signatureName>/s/ Susan Shelton</signatureName>
        <signatureDate>2021-12-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
