He moved to London with his family in 1946. He came from a large family and started his career with Ron Smyth, who was a trainer in Epsom. He will be best remembered as the jockey who won the 1,000 Guineas, 2,000 Guineas, Epsom Oaks (twice), Coronation Cup, and Prix de l'Arc de Triomphe. Most watchers of the sport of horse racing would consider that his greatest moment came in 1971 when he rode Mill Reef to win The Derby. He was regarded as one of Europe's leading jockeys between 1953 and 1979.
Geoff Lewis retired as a jockey in 1979, after which he applied for a trainer's licence and began to train at Thirty Acre Barn, near Epsom racecourse. He trained almost 500 winners before his retirement to Spain in 1999. In 2014 he moved back to Cranleigh, to be near his daughter in Ewhurst.