George Ainsley,a centre forward, played for his local side South Shields St. Andrews before joining Sunderland in April 1932. He made his league debut on 6 May 1933 in a 1-1 draw away to Chelsea. He played three more times the following season, in games against Portsmouth, Stoke City and Manchester City, but failed to feature again for Sunderland.
He left to join Bolton Wanderers in August 1936. In December the same year, after just seven league games for Bolton, Ainsley moved to Leeds United. He scored on his league debut (On 19 December against Sunderland) and scored twice in his second appearance (as Leeds beat Middlesbrough).
He was never a regular at Elland Road, despite scoring 30 times in 89 league games. He remained with Leeds until after the war, joining Bradford Park Avenue in November 1947. He retired from playing in 1949, having scored 29 goals in 44 games for Bradford Park Avenue.
After retiring as a player, Ainsley travelled the world as a coach. He began coaching in India in 1950, returning to coach the football team at Cambridge University in the early 1950s. In Bergen, he trained the Norwegian team SK Brann half of 1955. He was head coach of Ghana between 1958 and 1959. He was later coach of the Pakistan national team until November 1962 when he moved to Highland Park, Johannesburg as coach. Late in 1963 he became the manager of the Israel national side, leaving that post in December 1964.
He was appointed manager of Workington in June 1965, guiding the side to their highest ever league position (5th in Division Three) the following season. However, Workington were relegated at the end of the 1966-67 season and Ainsley was sacked in November 1966. He then coached USL Dunkerque in France.