Mull broke into show business as a songwriter, penning Jane Morgan's 1970 country single, 'A Girl Named Johnny Cash', which peaked at No. He studied painting and graduated in 1965 from the Rhode Island School of Design with a Bachelor of Fine Arts in 1967, he earned a Master of Fine Arts in painting, also from RISD.
There he attended and graduated from New Canaan High School. They lived there until he was 15 years old, when his family moved to New Canaan, Connecticut. He moved with his family to North Ridgeville, Ohio, when he was two years old. Mull was born in Chicago, the son of Betty Mull, an actress and director, and Harold Mull, a carpenter.
