He was noted for having beaten Jack Nicklaus twice in one day in singles match play, during the 1975 Ryder Cup on 21 September, winning 4&2 in the morning round and 2&1 in the afternoon session.

[4] Barnes became one of the "Butten boys", a group of young British professional golfers who were part of a training programme, funded by Ernest Butten, an entrepreneur and joint founder of PA Consulting Group.

Starting in 1963, Butten had funded a residential golf school at Sundridge Park in Bromley, Kent.

[5] After turning professional Barnes continued to be considered an English golfer, representing England in the 1967 R.T.V.

[12][13] Barnes completed all four rounds of the Open Championship 16 times in succession from 1967 to 1982 and had three top ten finishes, the best of them a tie for fifth in 1972.

Barnes played for Great Britain & Ireland and finally Europe in six consecutive Ryder Cup matches from 1969 to 1979.

After the 1984 season, when Barnes fell to 79th on the Order of Merit ranking, he only played a few tournaments the following year and retired to run a golf course in Sussex, England together with Max Faulkner; West Chillington.

He won the Senior British Open Championship in 1995, and became, the following year, the first man to successfully defend the title.

After having heavy alcohol drinking habits during his life and golf career, in early 1993, Barnes checked himself in for a successful drying-out period, remained sober and continued his golf career, two years later with great success in senior tournaments.