 Tsoumanis began his pro career in 2018, during the 2017–18 season, with the Greek Basket League club Olympiacos.For the 2019–20 season, he was assigned to play in the Greek 2nd Division, with Olympiacos' reserve team, Olympiacos B.

Tsoumanis played with the junior national teams of Greece.With Greece's junior national teams, he won a gold medal at the 2017 FIBA U16 European Championship Division B.