Galloway attended Salesian College Preparatory in Richmond, California, where he averaged 15 points, eight rebounds and three blocks as a senior.

[2] As a senior in 2018–19, he was named the Big West Conference Defensive Player of the Year for the third season in a row,[2] becoming the first three-time recipient of the honor.

He averaged 8.2 points, 8.9 rebounds, 1.5 blocks and 1.2 assists per game and helped the Bears win the Basketligaen title.

[3] In the 2020–21 season, Galloway started with Zadar in Croatia before joining Swiss team Monthey-Chablais in November 2020.

[4] In the 2021–22 season, Galloway started with Turkish club TED Ankara Kolejliler[5] before joining Finnish team Bisons Loimaa in November 2021.