Mack averaged 5.1 points and 2.0 rebounds per game as a freshman at Texas, helping the team reach the NCAA Tournament. As a sophomore, he averaged 14.8 points and 4.8 rebounds per game before being suspended indefinitely for violating team rules in January 2017. Following the season, Mack transferred to Alabama. He averaged 9.0 points and 3.3 rebounds per game. Mack transferred to Clemson for his redshirt senior season, partially to be closer to his mother.[1] On January 28, 2020, he scored a career-high 32 points in a 71-70 win against Syracuse.[2] As a senior, Mack finished second on the team in scoring and rebounding with 12.2 points and 5.2 rebounds per game.[3]
On February 4, 2023, he joined Apollon Patras of the Greek Basket League.[6] On March 25, 2023 Mack scored 27 points in a huge win over local rivals Promitheas Patras. In a total of 5 league games, he averaged 18.8 points (shooting with 45% from the 3-point line) and 2.8 rebounds, playing around 29 minutes per contest.
Mack was a part of the Clemson team chosen to represent the United States in the 2019 Summer Universiade in Italy. The U.S. received a gold medal after defeating Ukraine in the title game, and Mack averaged 9.5 points and four rebounds per game.[9]