Kenneth Robert ("Ken") Rosewall AM, MBE (born 2 November 1934) is a former world top-ranking amateur and professional tennis player from Australia. He won a record 23 tennis Majors including 8 Grand Slam singles titles and before the Open Era a record 15 Pro Slam titles and a record 35 Major finals overall. He won the Pro Grand Slam in 1963. Rosewall won 9 slams in doubles with a career double grand slam. He is considered to be one of the top male tennis players of all time. He had a renowned backhand and enjoyed a long career at the highest levels from the early 1950s to the early 1970s. Rosewall was one of the two best male players for about nine years and was the World No. 1 player for a number of years in the early 1960s. He was ranked among the top 20 players, amateur or professional, every year from 1952 through 1977. Rosewall is the only player to have simultaneously held Pro Grand Slam titles on three different surfaces (1962–1963). At the 1971 Australian Open he became the first male player during the open era to win a Grand Slam tournament without dropping a set.
A natural left-hander, he was taught by his father to play right-handed. Perhaps as a result of this unorthodox training (or in spite of it), he developed a powerful and effective backhand but never had anything more than an accurate but relatively soft serve. He was 1.70 m (5 ft 7 in) tall, weighed 67 kg (148 lb) and was ironically nicknamed "Muscles" by his fellow-players because of his lack of them. He was, however, fast, agile, and tireless, with a deadly volley. His sliced backhand was his strongest shot, and, along with the very different backhand of former player Don Budge, has generally been considered one of the best, if not the best, backhands yet seen.
The father of Brett and Glenn Rosewall, and grandfather of five, Rosewall now lives in northern Sydney.