POWER OF ATTORNEY
      The undersigned hereby constitutes and appoints each of John M. Donnan, Cherrie I. Tsai
and Troy B. Lewis, or any of them, signing singly, the undersigned's true and lawful attorney-in-
fact to:
1.    to the extent the undersigned does not have the access codes necessary to file on
EDGAR, execute for and on behalf of the undersigned a Form ID and any other form
required to be filed or submitted in accordance with Regulation S-T promulgated by
the United States Securities and Exchange Commission (the "Commission") in order
to obtain such codes; and
2.    execute for and on behalf of the undersigned, in the undersigned's capacity as an
officer and/or director of Kaiser Aluminum Corporation (the "Company"), Forms 3, 4
and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934 and
the     rules thereunder;
3.    do and perform any and all acts for and on behalf of the undersigned that may     be
necessary or desirable to complete and execute any such Form ID or Form 3, 4 or 5
and timely file any such form or forms with the Commission and any stock exchange
or similar authority; and
4.    take any other action of any type whatsoever in connection with the foregoing     that, in
the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or
legally required by the undersigned, it being understood that the documents executed
by such attorney-in-fact on behalf of the undersigned pursuant to this power of
attorney shall be in such form and shall contain such terms and conditions as such
attorney-in-fact may approve in such attorney-in-fact's sole discretion.
      The undersigned hereby grants to each such attorney-in-fact and any of them full power
and authority to do and perform any and every act and thing whatsoever, necessary or desirable
to be done in the exercise of any of the rights and powers herein granted, as fully to all intents
and purposes as the undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that any such attorney-in-fact, or
any such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted.  The undersigned
acknowledges that none of the foregoing attorneys-in-fact, in serving in such capacity at the
request of the undersigned, are assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities Exchange Act of 1934.
      The execution by the undersigned of this power of attorney hereby expressly revokes and
terminates any powers of attorney previously granted by the undersigned with respect to a Form
ID or Forms 3, 4 and 5 involving Company securities.  This power of attorney shall remain in
full force and effect until the undersigned is no longer required to file a Form ID or Forms 3, 4
and 5 with respect to the undersigned's holdings of and transactions in securities issued by the
Company, unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.
      IN WITNESS WHEREOF, the undersigned has caused this power of attorney to be
executed as of the 16th day of September, 2019.

/s/ Leo W. Gerard
Name:  Leo W. Gerard