 He retired from motorcycle racing at the completion of the 1961 season and turned his attention to auto racing.He was also a member of the AMA (American Motorcycle Association District 36) Sanctioned San Jose Motorcycle club (The Don's) which includes such famed alumni as Sam Arena, Tom Sifton, Kenny Eggers and Sam Arena Jr.

Leonard would make his USAC National Championship debut during the 1964 season when he competed in five races for various teams.Leonard would get a best finish of 5th at the season-ending Bobby Ball Memorial at Phoenix International Raceway driving the #65 Travelon Trailer Christensen-Offenhauser.