Jack began racing at the age of nine and amassed numerous national titles. Among these titles are: Junior Omnium in 1959, Senior Omnium in 1964, Senior Sprints in 1965 and 1967, 10 Mile in 1969, Masters Road in 1979, and Masters Sprint, Kilo and Pursuit Champion in 1988. Simes has held American records for 100 meters, one kilometer and 50 miles. He was a member of two Pan American, three Olympic and eight World Champion Teams. At both the 1967 Pan American Games and the 1968 World Championships he won the Silver Medal in the Kilo.
He has been a coach, advisor, promoter, Velodrome director and the author of Winning Bicycle Racing. He is currently the executive director of USPRO and a member of the International Professional Cycling Federation Executive Committee.