<SEC-DOCUMENT>0000860413-22-000087.txt : 20220315
<SEC-HEADER>0000860413-22-000087.hdr.sgml : 20220315
<ACCEPTANCE-DATETIME>20220315172621
ACCESSION NUMBER:		0000860413-22-000087
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220311
FILED AS OF DATE:		20220315
DATE AS OF CHANGE:		20220315

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Harrison William Scott Trust
		CENTRAL INDEX KEY:			0001908873
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22742363

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103
		BUSINESS PHONE:		406-831-6855

	MAIL ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Scott Jonathan R
		CENTRAL INDEX KEY:			0001361935

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22742365

	MAIL ADDRESS:	
		STREET 1:		P.O. BOX 30918
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04
		CENTRAL INDEX KEY:			0001908962
		STATE OF INCORPORATION:			WY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22742361

	BUSINESS ADDRESS:	
		STREET 1:		BOX 190
		CITY:			DAYTON
		STATE:			WY
		ZIP:			82836
		BUSINESS PHONE:		307-752-5605

	MAIL ADDRESS:	
		STREET 1:		BOX 190
		CITY:			DAYTON
		STATE:			WY
		ZIP:			82836

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Harper Grace Scott Trust
		CENTRAL INDEX KEY:			0001908895
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22742364

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103
		BUSINESS PHONE:		406-831-6855

	MAIL ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Holland Elizabeth Scott Trust
		CENTRAL INDEX KEY:			0001908953
		STATE OF INCORPORATION:			WY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22742362

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103
		BUSINESS PHONE:		406-831-6855

	MAIL ADDRESS:	
		STREET 1:		PO BOX 7113
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59103

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
		CENTRAL INDEX KEY:			0000860413
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				810331430
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918
		BUSINESS PHONE:		4062555300

	MAIL ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
		DATE OF NAME CHANGE:	19930615
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_164737956252015.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-03-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000860413</issuerCik>
        <issuerName>FIRST INTERSTATE BANCSYSTEM INC</issuerName>
        <issuerTradingSymbol>FIBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001361935</rptOwnerCik>
            <rptOwnerName>Scott Jonathan R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 7113</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BILLINGS</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001908895</rptOwnerCik>
            <rptOwnerName>Harper Grace Scott Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 7113</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BILLINGS</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001908873</rptOwnerCik>
            <rptOwnerName>Harrison William Scott Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 7113</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BILLINGS</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001908953</rptOwnerCik>
            <rptOwnerName>Holland Elizabeth Scott Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 7113</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BILLINGS</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001908962</rptOwnerCik>
            <rptOwnerName>Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4 CANYON VIEW DRIVE,  SHERIDAN, WY 82801</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SHERIDAN</rptOwnerCity>
            <rptOwnerState>WY</rptOwnerState>
            <rptOwnerZipCode>82801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>39.25</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14160</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>297439</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4, if any, together with Jonathan R. Scott with the indication of direct or indirect ownership in Tables I and II being made from Jonathan R. Scott's perspective.  The nature of beneficial ownership is described in detail by footnote for all reporting persons.</footnote>
        <footnote id="F2">Composed of 94,863 shares held of record by Holland Elizabeth Scott Trust, 94,863 shares held of record by Harper Grace Scott Trust, 94,863 shares held of record by Harrison William Scott Trust, and 12,850 shares held of record by IXL Limited Liability Company.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>JONATHAN R. SCOTT, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HARPER GRACE SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HARRISON WILLIAM SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HOLLAND ELIZABETH SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>JONATHAN SCOTT AS TRUSTEE OF THE JONATHAN R SCOTT TRUST DATED AS OF 4/21/04, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
