Born in Newbury, Leonard followed his father Maurice into speedway.^[2] He started his career with second half rides at Oxford in 1962, and made his league debut later that year, riding for Poole Pirates and Swindon Robins.^[3] His first two years in speedway were marred by injury, suffering two collarbone breaks, and he missed four and a half months in 1963 with two broken bones in his left leg.^[2] In 1965 he signed for West Ham Hammers, where he steadily improved, averaging over seven points per match in the 1967 season.^[3] After a spell with Hackney Hawks in 1969, he moved on to Wembley Lions in 1970, also riding for Newport Wasps for a period.^[3] He moved to Swindon Robins in 1972, but by 1974 his average had dropped below four points.^[3] He was signed by Leicester Lions in 1975 but released after a poor run of results, due in part to a back injury, which led to his retirement from the sport.^[4] He returned in 1976 and fared better after dropping down to the National League with Oxford Cheetahs,^[5] averaging over seven points. The following year he scored less well, and after two matches in 1978 he retired.^[6]