Enfield born goalkeeper Martin Grainger was with Norwich's youth team until 2009 when he left to join the set-up at Leyton Orient. He is the son of former Birmingham City left-back Martin Grainger

in September 2011, Grainger was called up to an England training camp, something he has attended twice since. He won an Under-18 cap in March 2014

He had loan spells at Cray Wanderers, Histon and Farnborough (three times) before making his Leyton Orient debut in September 2015 in the Football League Trophy, He had been given his first professional contract in May 2014. He went on to play 26 games for Orient (as well as having a further loan spell, this time at Hampton & Richmond Borough)

On 25th June 2019 he joined National League South side Dulwich Hamlet. He stayed with Hamlet until the summer of 2023. He spent the 2023/24 season at Hastings United, making 53 appearances. He transferred to Wingate and Finchley of the Isthmian League on 23rd August 2024.