In August 2015, Tsalmpouris signed a five-year contract with the
Greek Basket League club
AEK Athens. Tsalmpouris then became automatically
draft eligible 2 years early, due to having played a year of
professional basketball, right after a year of
college basketball in the
NCAA Division I, as well as previously playing under a start-up national basketball league, before participating in college basketball. So he was thus automatically entered into the
2016 NBA draft, but was not drafted after two rounds. In 2017, he was
loaned by AEK to the Greek club
Kolossos Rodou. He returned to AEK for the 2018–19 season, and with them he won the
2019 FIBA Intercontinental Cup, before going back to Kolossos, on a free transfer in the summer of 2019. On September 12, 2020, Tsalmpouris signed with the Greek club
PAOK Thessaloniki. On December 3, 2020, he recorded a then career high of 22 points against
Aris Thessaloniki. On August 22, 2021, Tsalmpouris moved to the Greek club
Apollon Patras, where he enjoyed a very successful 2021–22 season campaign. In a total of 24 Greek Basaket League games played, he averaged 14.9 points, and 5.6 rebounds per game, while playing an average of around 32 minutes per contest. On September 23, 2022, he signed with
Real Betis of the Spanish
Liga ACB. On February 17, 2023, he parted ways with the club. In 16 games played with Real Betis, he averaged 8.8 points and 2.9 rebounds per contest. On February 26, 2023, he signed with
Bilbao of the Spanish
Liga ACB. On July 25, 2024, Tsalmpouris returned to Greece for
Panionios. He renewed his contract for one more year on June 14, 2025. ==National team career==