[4][5][6] The Oakland Athletics selected Mitchell in the 14th round (411 overall) of the 2017 Major League Baseball draft, but he opted not to sign with the team and attend UCLA.

[16] Mitchell entered his junior season on the watch list for the Golden Spikes Award and as a top prospect for the 2020 Major League Baseball draft.

[17][18] Mitchell batted .355 with nine RBIs and 18 runs with five stolen bases before the season was cut short due to the coronavirus pandemic.

[19] The Milwaukee Brewers selected Mitchell in the first round, with the twentieth overall pick, in the 2020 Major League Baseball draft.

[21] Mitchell was named to Milwaukee's 2021 Spring Training roster as a non-roster invitee and batted .367 with one home run and six RBI in 22 games.

[27] He suffered an oblique injury in May and was placed on the injured list until July 7, 2022, after a rehab assignment with the Arizona Complex League Brewers.

[30] He missed the phone call from Sounds manager Rick Sweet informing him of his promotion to the majors, telling reporters it was because he was eating a chocolate chip cookie.

In 2024, Mitchell suffered a broken left hand in spring training and was placed on the injured list to begin the season.

[43] Later that year, his most memorable MLB moment occurred on October 2nd when his two-run home run with two outs in the bottom of 8th carried the Brewers to a 5-3 victory over the New York Mets in Game #2 of the Wildcard series.