Gary Stevens was born in Hillingdon, Middlesex and attended Thurston Upper School in Suffolk. He joined Brighton & Hove Albion in 1977. Gary made his debut as a 17-year-old on 15 September 1979, in the First Division as Brighton won 2–0 at home to Ipswich Town, the club which had released him as a schoolboy. A versatile defender who could also play in midfield, he made 26 appearances in his first season, scoring once, and remained a regular in the side.
In 1983, Brighton, already relegated to the Second Division, played in the FA Cup final for the first time in their history. Losing to Manchester United, 2–1 with three minutes of normal time remaining, Gary equalised, and teammate Gordon Smith missed an easy chance to win the game at the end of extra time, remembered for the commentator’s line “And Smith must score…” Brighton lost the replay 4–0, and Gary joined Tottenham Hotspur for a fee of “about £350,000”.
Gary made his Tottenham debut at the start of the 1983-84 season, again against Ipswich, but this time was on the losing side. He was a first team regular that season, making 40 league appearances and scoring four goals, and played on the winning side in the 1984 UEFA Cup Final scoring his penalty in the shootout, He was also in the side that suffered an unlikely 3–2 defeat to Coventry City in the 1986 FA Cup Final.
He was also capped seven times by England, and was included in the squad for the 1986 World Cup.
Gary left Spurs for Portsmouth in 1990 but persistent injuries forced him to retire in 1992.