[3] Martin moved to Wimbledon of the First Division aged 17 in 2003, shortly before the club relocated to Milton Keynes in September of the same year.

Martin was handed his professional debut by manager Stuart Murdoch on 19 April 2004, a 2–0 loss away to Burnley, whilst the club were still playing as Wimbledon.

[6] However, he was injured within five minutes of his debut, without even touching the ball, against Lincoln City, damaging his ankle which ruled him out for the rest of his loan spell and he returned to Liverpool.

[7] After regaining his fitness he returned to Accrington on loan for the rest of the season,[8] making his comeback in a 1–0 win over Torquay United,[9] and helping the club avoid relegation to the Conference National.

[10] On 6 November 2007, Martin was on the bench when Liverpool beat Turkish club, Beşiktaş 8–0 at Anfield in their UEFA Champions League group match.

He made his debut for Leeds in the Football League Trophy Northern Section semi-final at Elland Road against Accrington Stanley.

[19] On 24 December he extended his loan by a further month, until 30 January, and Liverpool also gave him permission to play for Leeds against Manchester United in the FA Cup.

He kept his place for a 2–2 draw with Middlesbrough but the return of Bywater, combined with the allowance of only five loan players in the match day squad when Derby had six, saw Martin uninvolved with the first team for the remainder of his month at the club.

[25] On 3 June 2019, Martin signed a two-year contract with Premier League side West Ham United, to provide cover for first choice keepers Łukasz Fabiański and Roberto.

[31] He reunited with Dean Lewington, whom he played alongside for both Wimbledon and Milton Keynes Dons in 2004, and subsequent years for the latter club.

[33] Martin joined Southend United on non-contract terms at the start of the 2023–24 season in a goalkeeping coach role.

[35] Having played nine games for Southend, in July 2024 Martin joined newly promoted Premier League team Ipswich Town in a player-coach capacity.