POWER OF ATTORNEY

      Know all by these presents, that the undersigned hereby constitutes each
of Michelle Hook and Susan Shelton, with full power of substitution, the
undersigned's true and lawful attorneys-in-fact to:

   1. prepare, execute in the undersigned's name and on the undersigned's
      behalf, and submit to the U.S. Securities and Exchange Commission (the
      "SEC") a Form ID, including amendments thereto, and any other documents
      necessary or appropriate to obtain codes and passwords enabling the
      undersigned to make electronic filings with the SEC of reports required by
      Section 16(a) of the Securities Exchange Act of 1934 or any rule or
      regulation of the SEC;

   2. execute for and on behalf of the undersigned with respect to Portillo's
      Inc. (the "Company"), Schedules 13D and 13G and Forms 3, 4, and 5 in
      accordance with Sections 13 and 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 which
      may be necessary or desirable to complete and execute any such Schedules
      13D or 13G or Form 3, 4, or 5, complete and execute any amendment or
      amendments thereto, and timely file such form with the SEC and any stock
      exchange or similar authority; and

   4. take any other action of any type whatsoever in connection with the
      foregoing which, 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
      discretion.

      The undersigned hereby grants to each attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper 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 such attorney-in-fact, or 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 the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming any of the undersigned's responsibilities to comply
with Sections 13 and 16 of the Securities Exchange Act of 1934.

      This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file 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 this 4th day of October, 2021.

                                  Very truly yours,


                                               /s/ Michael Osanloo
                                              ---------------------------------
                                              Name: Michael Osanloo