James Scott Connors was born on 2 September 1952 in East St. Louis, Illinois, across the Mississippi from St. Louis (some sources give nearby Belleville). His father worked as a toll-bridge attendant and was the son of the city's mayor; his mother Gloria, a teaching professional who had learned the game from her own mother Bertha, raised him to be a tennis player and remained his main coach throughout his career. In 1968 she took him to Southern California to be coached by Pancho Segura, and he also trained at times with Pancho Gonzales.
By 1974, his second year as a professional, he was winning majors: the Australian Open, Wimbledon and the US Open. He had no chance at the Grand Slam, because he was barred from that year's French Open after signing to play World Team Tennis. In 1974 he became world No. 1 and held the ranking for a then-record 160 consecutive weeks, until 1977.
His weapons were a two-handed backhand, an indomitable fighting spirit and what many considered the best return of serve in the game, along with a temper and on-court antics that drew as much attention as his tennis. His great rivals were John McEnroe, Björn Borg and Ivan Lendl. He won the US Open five times, in 1974, 1976, 1978, 1982 and 1983, and he is the only player to win it on three different surfaces: grass, clay and hard court. In 1982 he won Wimbledon again, eight years after his first title there.
He won eight major singles titles in all, five US Opens, two Wimbledons and one Australian Open, and he still holds three Open Era records: 109 singles titles, 1,557 matches played and 1,274 matches won. His most famous late run came at the 1991 US Open, where he celebrated his 39th birthday and, against players half his age, reached the semifinals.