Mason was drafted in the fifth round, 39th overall, by the Montreal Alouettes in the 2023 CFL Draft and signed with the team on May 11, 2023.[2] Following 2023 training camp, he returned to McMaster to complete his university eligibility.[3] He then returned to the Alouettes later that season when he re-signed on October 5, 2023.[4] Mason finished the season on the practice roster as the Alouettes won the 110th Grey Cup.[3] He then re-signed with the team on November 27, 2023.[3]
In 2024, Mason made the opening day roster and made his professional debut on June 7, 2024, against the Winnipeg Blue Bombers.[3]