He was 1.70 m (5 ft 7 in) tall, weighed 67 kg (148 lb), and sarcastically was nicknamed "Muscles" by his fellow-players because of his lack of them; however, he was fast, agile, and tireless, with a deadly volley.

[20][21] In September 1950, at the age of 15, and still a junior player, Rosewall reached the final of the 1950 New South Wales Metropolitan hard court championships, where he lost to Jim Gilchrist.

[23] Rosewall won his first men's tournament in Manly, New South Wales in January against Gilchrist and was "the youngest player ever to capture the seaside title.

"[24] Rosewall beat Adrian Quist in the semifinals of the Brisbane exhibition tournament in August,[25] but he lost the final to Lew Hoad.

[27] In the New South Wales championships in November, Rosewall pushed reigning Australian and Wimbledon champion Dick Savitt to four sets.

[30] Rosewall was only 18 years old when he won his first singles title at a Grand Slam event in 1953, defeating American Vic Seixas in the semifinals and compatriot Mervyn Rose in the final of the Australian Championships.

[39] Rosewall played "a fine net game" in beating Mal Anderson in the final of the Darling Downs tournament in April.

Promoter and former tennis great Jack Kramer tried unsuccessfully to sign the "Whiz Kids" (Lew Hoad and Rosewall) to professional contracts in late 1955.

[55] At the Forest Hills Tournament of Champions, a round-robin event held in New York, Rosewall defeated Segura and Hoad but lost to Gonzales, Sedgman and Trabert to finish in joint third place.

Rosewall tied for second (with Pancho Gonzales and Sedgman) behind an undefeated Segura in the Masters Round Robin Pro in Los Angeles in July.

This tournament returned in 1958, and Rosewall beat Jack Kramer, Frank Sedgman, and an injured Lew Hoad in four sets to claim the title.

[64] At the Roland Garros World Professional Championships, Rosewall lost in the semifinals to Trabert, and was beaten by Hoad in the third place match.

[68][69] Halfway through the North American part of the tour the standings were Gonzales 23–1 (his only match lost in three sets to Olmedo in Philadelphia), Segura 8-9, Rosewall 11–13.

He trained his long-time friend Hoad when the pros toured in Australia where Gonzales, back to the courts after a 7+1⁄2-month retirement, won another World tour featuring Hoad (withdrew with injury), Olmedo (replacing Rosewall), Gimeno and the two new recruits MacKay and Buchholz (Segura, Trabert, Cooper and Sedgman sometimes replaced the injured players).

After having won on clay and on wood Rosewall ended the season by winning on grass at the New South Wales Pro Championships in Sydney, defeating Butch Buchholz in the final, cementing his status as the best all-court player that year.

[88] Per records found, Rosewall lost seven matches in 1962: Hoad (in the Adelaide Professional Indoor Tournament), Gimeno, Ayala, Buchholz, Segura, Anderson and Robert Haillet.

[90] In an Australasian tour (Australia and New Zealand) played on grass for the Australian portion, Rosewall defeated Rod Laver 11 matches to 2.

A US tour followed with Rosewall defending his world pro title[91][92][93][94] against Laver, Gimeno, Ayala and two Americans: Butch Buchholz and Barry MacKay (Hoad was recovering from a shoulder injury).

At the end of the South African tour in October, Rosewall also beat Laver in three straight sets in a special challenge match, on cement, held in Ellis Park, Johannesburg.

[107] In early 1965 the pro circuit toured Australia and a number of defeats to Laver and Gonzales created some doubt about the continuation of Rosewall's dominance.

[108] In late April-early May Rosewall competed in the US Pro Indoors, held at the Seventh Regiment Armory in New York and part of a nine-tournament US circuit.

At Wimbledon, Rosewall lost in the third round to Bob Lutz and "confessed that for the first time in his career the fans disturbed his concentration".

[141] After his runner-up finishes at Sydney and Wimbledon and his victory at the US Open in 1970, Rosewall continued his good performances in 1971 in the great grass court tournaments.

Only Stan Smith (Army's service), Cliff Richey, Clark Graebner, and the clay specialist players Ilie Năstase and Jan Kodeš were missing.

The US Open, won by Ilie Năstase, was the greatest event of the year as only in this tournament were all the best players present with the exception of Tony Roche who suffered from a tennis elbow.

Later that year two other tournaments had good fields with WCT and independent pros: the Pacific Southwest Open at Los Angeles and, to a lesser extent, Stockholm, both won by Stan Smith.

Rosewall won the last major title of his long career by defeating Laver in an epic five-set match which was decided by a tiebreak.

[184] Rosewall made a brief comeback at 47 years of age in a non-ATP tournament, the New South Wales Hardcourt Championships in Grafton in February 1982, where he reached the final, losing to Brett Edwards in two sets.

[b] In 1988, a panel consisting of Bud Collins, Cliff Drysdale, and Butch Buchholz ranked their top five male tennis players of all time.

[198] Ken Rosewall joined professional tennis in 1957 and was unable to compete in 45 Grand Slam tournaments until the open era arrived in 1968.