A natural athlete, as a boy Newcombe played several sports until devoting himself to tennis. He was the Australian junior champion in 1961, 1962 and 1963 and became a member of Australia's Davis Cup winning team in 1964. He won his first Grand Slam major in 1965 by taking the AustralianChampionships doubles title with fellowAustralian Tony Roche. That same year, the duo won the Wimbledon doubles title. Together, Newcombe and Roche won 12 Grand Slam titles, more than any other men's team in tennis history.

John Newcombe was the last of the Australians who dominated tennis in the 1950s and 1960s, using a powerful serve and volley style. As a pro, Newcombe was the joint world No. 1 player in 1970 and 1971. In singles play, he was a two time winner of the Australian Open, a three time winner of Wimbledon, and the US Open twice.