In the 2020–21 season, Dieng averaged 12.6 points, 5.8 rebounds, and 2.9 assists per game for Centre Fédéral in the Nationale Masculine 1.

[4] On 1 June 2021, Dieng announced that he would play for the New Zealand Breakers of the National Basketball League (NBL) in the 2021–22 season, alongside fellow Frenchman and eventual 2022 NBA draft selection Hugo Besson.

He became the first European player to join the league's Next Stars program to develop NBA draft prospects.

[7] On 15 April 2024, he won the NBA G League title with the Oklahoma City Blue and was named the championship game most valuable player after getting 25 points, six boards, four assists and two blocks in the win against the Maine Celtics.

He averaged 8.9 points, 3.6 assists and 2.7 rebounds per game, helping his team win the silver medal.