John Patrick McEnroe was born on 16 February 1959 in Wiesbaden, West Germany, where his father was stationed with the US military, the eldest of three McEnroe boys. He announced himself in 1977, at 18 and still an amateur: he won the French Open mixed doubles and then qualified for Wimbledon and went all the way to the semifinals, the youngest player and the first qualifier ever to get that far, before Jimmy Connors stopped him. He took no prize money, to keep his amateur status, and went to Stanford, where in 1978 he won the national college singles title and led the team to the NCAA championship. He turned professional straight afterwards.
He won the US Open in 1979, 1980 and 1981 and Wimbledon in 1981, 1983 and 1984. His 1980 Wimbledon final against Björn Borg, which he lost in five sets, is remembered as one of the great matches. His best year was 1984: he won 13 of the 15 singles tournaments he entered, his third Wimbledon and fourth US Open among them, with a record of 82 wins and 3 losses. The one big loss was the French Open final, to Ivan Lendl. He won the season-ending Masters three times, in 1978, 1983 and 1984.
He was just as strong in doubles. With Peter Fleming he won seven of his nine major men's doubles titles, and his 77 singles and 78 doubles titles make him the Open Era's overall leader in tournament wins, 155 in all. He was a workhorse for the United States in the Davis Cup, playing singles and doubles, with a record of 41–8 in singles and 18–2 in doubles, and he was on the winning team in 1978, 1979, 1981, 1982 and 1992. His temper made headlines as often as his tennis and earned him the nickname "Superbrat".
When he left the tour in 1992 he had won seven major singles titles and 17 major titles in all, counting his doubles and his French Open mixed title.