Milne was the first American motorcycle racer to win a world championship. In 1937, he took the Speedway World Championship at Wembley Stadium in front of 85,000 fans. Four years earlier, Milne and younger brother Cordy had bought a pair of Comerford-JAP bikes from England and went racing. They both became stars. In 1935, Cordy edged Jack for the American Speedway National Championship. The following year Jack won the American title — and the Australian title over fellow American Wilbur Lamoreaux. When Jack won the world title in 1937, it was over Lamoreaux and Cordy. He narrowly missed repeating in ‘38. With the onset of WWII, the Milnes returned to the US and opened a motorcycle shop. The sport’s popularity plummeted. Milne helped revive it in the late 1960s by bringing Speedway World Champions Ivan Mauger and Barry Briggs for a series of exhibitions. He lived long enough to see Bruce Penhall and Sam Ermolenko follow in his footsteps as American World Speedway Champions. Milne was inducted into the AMA Hall of Fame in 1998.