POWER OF ATTORNEY

     KNOW ALL BY THESE PRESENTS, that the undersigned hereby makes, constitutes
and appoints Steven M. Weddell and Brad A. Gazaway, signing singly, the
undersigned's true and lawful attorneys-in-fact, with full power and authority
as hereinafter described on behalf of and in the name, place and stead of the
undersigned to:

  (i)   execute for and on behalf of the undersigned, in the undersigned's
        capacity as a director, director nominee, officer or beneficial owner of
        shares of common stock (the "Shares") of Leslie's, Inc., a Delaware
        corporation (the "Company"), any Schedule 13D or Schedule 13G, and any
        amendments, supplements or exhibits thereto (including any joint filing
        agreements) required to be filed by the undersigned under Section 13 of
        the Securities Exchange Act of 1934, as amended, and the rules and
        regulations promulgated thereunder (the "Exchange Act"), and any Forms
        3, 4, and 5 and any amendments, supplements or exhibits thereto required
        to be filed by the undersigned under Section 16(a) of the Exchange Act;

  (ii)  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 Schedule 13D, Schedule 13G, Form 3, 4, or 5 and timely file
        such forms with the United States Securities and Exchange Commission and
        any stock exchange on which the Shares are then listed; and

  (iii) take any other action of any type whatsoever in connection
        with the foregoing which, in the opinion of such attorneys-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 attorneys-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 attorneys-in-fact may approve in such
        attorneys-in-fact's discretion.

      The undersigned hereby grants to such attorneys-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 attorneys-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 Section 13 and Section 16
of the Exchange Act.

     This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file reports or schedules under Section 13
or Section 16 of the Exchange Act 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 28th day of October, 2020.

                                          /s/ Susan OFarrell
                                          ---------------------
                                          Susan O'Farrell