 Leffler drove Morris Coopers for many years in the 1960s.He finished second in the 1969 Rothmans 12 Hour Classic at Surfers Paradise driving a Morris Cooper S

In the early 1970s he turned his hand to Formula Ford racing a Bowin P6F in which he won the 1973 TAA Formula Ford Driver to Europe Series.In 1974 he contested the Australian Formula 2 Championship and finished third.