As a freshman, Mitchell helped Martin Luther King High School in Riverside, California win the CIF Southern Section Division 1A championship.

[3] Mitchell initially committed and signed a National Letter of Intent to play college basketball for Cal State Fullerton.

[3] On November 20, 2017, in his fourth collegiate game, Mitchell scored a career-high 31 points, 26 of which came in the second half, in a 94–63 win over Eastern Illinois.

He shot 7-of-11 from three-point range and scored the most points for a San Diego State freshman since Evan Burns in 2003.

[9] On February 1, 2020, Mitchell scored a junior season-high 28 points, including 24 in the second half, in an 80–68 win over Utah State.

[20] On June 27, 2024, Mitchell signed a two-year (1+1) contract with Žalgiris Kaunas of the Lithuanian Basketball League (LKL) and the EuroLeague.