Carson was born in Manitoba, Canada in 1910. His family soon moved to Milwaukee, and it was during his college years there that he developed a taste for performing. It was also in college that Jack met fellow character actor Dave Willock. The two of them eventually hit the vaudeville circuit, and in the late thirties, the team of Willock and Carson ended up in Hollywood, finding work in radio and in film.
Carson snagged a contract with RKO and worked there steadily throughout the rest of the decade, mostly in bit parts like “Policeman” (Everybody’s Doing It and Condemned Woman, both in 1938), “Truck Driver” (It Could Happen to You, 1937), and even “Roller Coaster Ride Attendant” (Maid’s Night Out, 1938).