Kenneth Robert Rosewall is an Australian former world No. 1 professional tennis player. Rosewall won 147 singles titles, including 23 majors: a record 15 Pro Majors and eight Grand Slam tournaments. He also won 15 Pro Majors in doubles and nine Grand Slam doubles titles. Rosewall achieved a Pro Slam in singles in 1963 by winning the three Pro Majors in one year, and completed the career Grand Slam in doubles.
Rosewall had a renowned backhand and enjoyed a long career at the highest levels from the early 1950s to the early 1970s. He was ranked as the world No. 1 men's tennis player by multiple sources from 1961 to 1964, multiple sources in 1970, and Rino Tommasi in 1971 and 1972. Rosewall was first ranked in the top 20 in 1952, and last ranked in the top 20 in 1977. Rosewall is the only player to have simultaneously held Pro Slam titles on three different surfaces (1962–63). At the 1971 Australian Open, he became the first man in the Open Era to win a Grand Slam tournament without dropping a set. Rosewall won world professional championship tours in 1963, 1964, and the WCT titles in 1971 and 1972. A natural left-hander, Rosewall was taught by his father to play right-handed.