[3] He was named All-Arizona Division 1 honoree by the Arizona Republic after leading Desert Vista to the championship game in 2015.

As a freshman he was named Mountain West Sixth Man of the Year by the league's head coaches after putting up 10.1 points and 7.3 rebounds in conference play.

On March 23, 2019, Clarke recorded a career-high 36 points alongside 8 rebounds, 5 blocks, and 3 assists in a 83–71 win over #9 seeded Baylor.

[9] With four double-doubles, he was named the most valuable player (MVP) of the 2019 NBA Summer League, becoming the second non-American to win the award.

[10] On October 23, 2019, Clarke made his NBA debut, coming off the bench in a 101–120 loss to the Miami Heat with eight points, seven rebounds, an assist and a block.

On May 29, during the Grizzlies' first round series against the Utah Jazz, Clarke made his playoff debut, playing seven minutes and grabbing one rebound in a 111–121 Game 3 loss.

[21] On April 29, he recorded 17 points, eleven rebounds, five assists and three blocks as the Grizzlies eliminated the Timberwolves from the playoffs with a 114–106 Game 6 win.

[23][24] On March 3, 2023, during a 113–97 loss to the Denver Nuggets, he suffered a left leg injury and exited the game after playing only two minutes.