“Signing Maurice is a key part of our strategy to build Canadian talent on our roster. He has a proven track record in the CEBL, and when given the right situation and opportunity, his production on the court will only go up,” said General Manager and Vice-President of Basketball Operations, Barry Rawlyk. “He is a high character guy with a lively personality who will be popular with our fans and his teammates alike.”

Calloo made his professional debut during the 2022 CEBL season with the Guelph Nighthawks (now Calgary Surge). During that season he played nine games, averaging 11.1 points, 2.7 rebounds, 19.8 minutes while shooting 50.7% from the field and 38.9% from behind the arc. During the CEBL postseason, he joined the Canadian National Team at the 2022 FIBA AmeriCup in Brazil. Canada reached the bronze medal game losing to the USA team with a final score of 84-80.

In 2022-23, Calloo signed a contract with the Salt Lake City Stars (Utah Jazz NBA G League-affiliate). After playing four games with the Stars, he signed with the Windy City Bulls (Chicago Bulls NBA G League-affiliate). After the NBA G League season, he returned to the CEBL to play with the Calgary Surge during their inaugural season in 2023. While with the Surge, he averaged 5.8 points, 2.7 rebounds, 14.2 minutes while shooting 42.5% from the field and 40.7% from behind the arc. The Surge captured a Western Conference Championship with a regular season record of 12-8. During the Championship Weekend Final, Calgary lost to the Scarborough Shooting Stars with a final score of 82-70.

After the 2023 CEBL season, Calloo signed with Grengewald Hostert of LBBL in Luxembourg. As a starter, he has appeared in 13 games averaging 26.4 points, 8.1 rebounds, 1.8 assists, 0.6 steals, 0.4 blocks in 34.2 minutes. He currently leads the team in points per game while shooting 48.9%.

Prior to his professional career, Calloo attended Oak Hill Academy as a senior and Huntington Prep for his sophomore and junior years. As a three-star recruit, he made his NCAA debut with Oklahoma State Cowboys appearing in 16 games. As a sophomore, he transferred to Indian Hills of NJCAA playing in 33 games averaging 9.1 points, 3.9 rebounds, and 20.8 minutes while shooting 45.6% from the field and 35.1% from behind the arc. Indian Hills were 2020 NJCAA D1 Region XI Champions with a 30-3 record, they were set to play in the National Tournament before Covid-19. As a junior, Calloo transferred to Oregon State University. The Beavers finished the 20-2021 regular season with a record of 20-13 which led them to the 2021 Pac-12 Championship. They played in the NCAA Tournament with an exit during the Elite Eight. Over two seasons with the Oregon State Beavers, he averaged 7.0 points, 2.9 rebounds in 19.3 minutes over 61 games.