After a brief amateur career, Jacklin turned professional at the start of 1962 and in 1963 was chosen by Henry Cotton as his Rookie of the Year.

Jacklin won the 1969 Open Championship at Royal Lytham in July, two strokes ahead of Bob Charles.

[9] At the start of 1962 Jacklin turned professional, becoming an assistant to Bill Shankland at Potters Bar Golf Club.

[15] Having been runner-up in 1963, Jacklin won the 1964 Coombe Hill Assistants' Tournament, a stroke ahead of Adrian Sadler.

[20] However weather meant that the event did not finish until the Monday and Jacklin was due to play in the Gor-Ray Cup, the Assistants' Championship, the following day, at Hartsbourne.

[32] Jacklin was selected, together with Peter Alliss, for the England team for the 1966 Canada Cup in Japan, the pair finishing in 10th place.

[40] Jacklin won twice on the 1967 British PGA circuit, the Pringle of Scotland Tournament and the Dunlop Masters, and he finished 5th, behind Roberto De Vicenzo, in the 1967 Open Championship.

[51] In October Jacklin made his debut in the Piccadilly World Match Play Championship, losing to Gary Player in the semi-finals, at the 37th hole.

At the final hole, Nicklaus conceded Jacklin's two-foot putt, halving the match, and ending the Ryder Cup with a tied score.

[44] That year Jacklin made his first appearances in the U.S. Open, although he had to qualify for the event, and in the PGA Championship, which was played at a later date than in 1968.

[62] He won $3,850, a sum that lifted him to 60th in the official money list with $33,036 and meant he was exempt from qualifying for PGA Tour events in 1970.

[63][50] In 1970 Jacklin won his second major title, the U.S. Open by seven strokes on a windblown Hazeltine National Golf Club course.

[50] Defending his title, Jacklin finished solo 5th in the 1970 Open Championship at St Andrews, three strokes behind the leaders.

Wills Tournament, lost to Jack Nicklaus in the semi-final of the Piccadilly World Match Play and won the Lancome Trophy.

[73] Jacklin again did well in the Open Championship at Royal Birkdale, finishing solo third, two stroke behind the winner, Lee Trevino.

[74] On the British circuit he won the Benson & Hedges Festival in August, beating Peter Butler in a playoff.

[76] Jacklin played twice with Brian Huggett on the opening day, winning one match and halving the other, as the team took a narrow lead.

[47] Jacklin partnered Peter Oosterhuis in the 1971 World Cup in Florida, the England team finishing tied for 6th place.

[82][83] He won the Viyella PGA Championship by 3 strokes from Peter Oosterhuis, and had three other top-5 finishes in British tournaments including being runner-up to Bob Charles in the Dunlop Masters.

[85] Jacklin had a poor start to the 1973 PGA Tour and was disqualified in the Dean Martin Tucson Open in January, after failing to enter a score for the final hole.

[82][93] Jacklin won £7,000 for his Italian Open win and £7,500 for being runner-up in the John Player Classic and led the prize money list for the season.

[47] In February 1974 Jacklin again played on the Caribbean Tour and in the last event he successfully defended the Los Lagartos Open.

[100] He played a few events at the start of 1978, including a tied for 8th place in the Bing Crosby National Pro-Am, but withdrew from the Doral-Eastern Open in March with a wrist injury and didn't return to the tour.

[103] Selection for the Great Britain and Ireland team in the 1975 Ryder Cup in America was based on performances in 1975 European Tour events.

The selectors chose Mark James, who had finished 11th in the list, and Peter Oosterhuis, who had recently won the Canadian Open.

The couple married in 1966, eleven months after their initial meeting at a Belfast hotel, and two days after Jacklin had won the Blaxnit (Ulster) Tournament.

"[114] Six weeks after his first wife's death, Jacklin met a 16-year-old waitress named Donna Methven at a golf tournament in England.

[115] Jacklin is also stepfather to Waagen's two children, daughter Anna May and son A.J., from her previous marriage to former Bee Gees guitarist Alan Kendall.

In 1971, Jacklin said that he received death threats from a caller who also threatened to bomb his wife's family home in Belfast.

The caller said that Jacklin would be shot if he played in the Gallaher Ulster Open, because his wife's family supported Ian Paisley.