[4][5] Playing basketball for the high school as a senior, Upson averaged 11.4 points, 9.8 rebounds, and 4.4 blocks per game.

[7] In his sophomore year, he averaged 10.8 points, 7.3 rebounds, and 1.7 blocks (2nd in NJCAA Region IX) per game.

[4] In 2019, he played for Comunicaciones Mercedes of Argentina's Liga, averaging 5.8 points, 5.3 rebounds, and 0.9 blocks per game.

[4][13][14] In 2019–20, he played for Asseco Arka Gdynia of the Polish Basketball League, averaging 7.6 points, 3.8 rebounds, and 1.0 blocks per game.

[4][15][16][17] In 2020, Upson played one game for Strasbourg IG of France's Jeep Elite, before the pandemic ended the season.

[4][18][19] In 2020–21, he played for Pallacanestro Trieste 2004 of Italy's Lega Basket Serie A,[4][20] and averaged 7.1 points, 4.8 rebounds, and 0.4 blocks per game.