Gray switched to rugby league with English club Wigan, and played at prop, scoring 4 conversions in their 19–9 victory over Salford in the 1973 Lancashire Cup Final during the 1973–74 season at Wilderspool Stadium, Warrington, on Saturday 13 October 1973.[5] Gray won caps for England (RL) while at Wigan in 1975 against France, and Wales, in the 1975 Rugby League World Cup against France,[2] and won caps for Great Britain (RL) while at Wigan in 1974 against France (sub) (2 matches), Australia (2 matches), Australia (sub), and New Zealand (3 matches).[3] Gray was one of the first players to introduce the now routine round-the-corner style of goal kicking to Australia, he won the 1976 Amco Cup 'superstar' prize for player of the competition, he was the 1982 Dally M Award-winninghooker, a series of broken forearms, and constant back pain ended his career in 1983.
John Gray was named on the bench in the North Sydney Bears Team of the Century.