Standing at 6 ft 10 in (2.08 m), he play at the power forward position for Básquet Coruña of the Spanish Liga ACB.

During his junior year, Thompkins decided to attend Oak Hill Academy where he averaged 15.8 points per game and 8.9 rebounds.

For his senior season, Thompkins averaged 27.5 points and 14.7 rebounds for Wesleyan as they won the Georgia High School Association Class AA state championship.

[1] Thompkins leveled out in his junior year statistically, while the Bulldogs eventually made it to the 2011 NCAA Men's Division I Basketball Tournament only to be eliminated 68–65 in the first round to the Washington Huskies.

Jay Bilas describes Trey Thompkins' body fat percentage as "pretty good if you're a sea lion."

Thompkins announced that he would leave Georgia and forgo his senior season to enter the 2011 NBA draft on April 5, 2011.

[9] From the start of the 2014–15 season, he saw a lot of trust from the team's head coach, Ainars Bagatskis, as he played at least 20 minutes per game, in both the VTB United League and the EuroLeague.

[citation needed] On August 26, 2015, Thompkins signed a one-year deal with the Spanish team Real Madrid.

[citation needed] On July 6, 2018, Thompkins re-signed a two-year deal with the Spanish team Real Madrid.