Simon made his racing debut in 1970 driving a second-hand Vollstedt chassis at Phoenix International Raceway but was sidelined by magneto failure after only 4 laps. He made his Indianapolis 500 debut that year and finished 14th position. At Ontario Motor Speedway that September, Simon captured his career-best finish of 3rd place and he finished 10th in the 1970 USAC National Championship. Simon would continue to be marginally competitive throughout the 1970s, never matching his finishes of the 1970 season. In 1979, Simon sided with USAC during its split with CART. In being one of the few drivers to complete the USAC schedule, Simon finished 8th in the Championship. In 1980 Simon moved to CART and continued to have little success throughout the 1980s while remaining marginally competitive. He logged his best CART season in 1987 when he made 11 starts and logged two top-tens including a 6th place at the Indy 500, good enough for 20th in the CART championship. A partial season in 1988 where Simon logged a solid 9th-place finish in the Indy 500 was his last as a driver.