mason began racing in motocross in 1992, when he was 4 years old. at the time he was too young to race in karting in north america, so motocross in canada in the cmrc was the only option. by the time mason hit his 8th birthday in 1995, he had won the ontario provincial motocross championship and the canadian national motocross championship. he did double duty in 1996, racing in both the cmrc and starting his first year in karting in the united states. that year he added another provincial championship to his motocross resume, and went on to take the new york state karting championship, forcing him to miss the canadian nationals in ’96. that led to focusing on 4 wheels from then on. in 1997, he began racing in the world karting association. mason took a multitude of wins as he progressed through the karting classes, including international wins in the 1999 constructor's cup. in 2002, he moved up to the skusa promoto tour in the 80cc shifterkart class with the mba karts team. in 2003, mason was picked up by the first kart north america team. he shifted his focus to the champ car stars of tomorrow karting championship. he also did some appearances in skusa that year, scoring pole positions in jacksonville and texas. mason won in the champ car series first time out, and went on to the champ car world finals in california to qualify pole and win the pre-final, before finishing 3rd in the final and taking 3rd in the overall championship.