Green made his first-team debut for Norwich City in 1999 and totalled 241 appearances across all competitions for them, making the PFA Team of the Year when they won the First Division in 2003–04.

In 2006, he transferred to West Ham United, making the same number of appearances in a six-year spell in which he was their Player of the Year in 2008 and won promotion via the Championship play-offs in 2012.

[3] He made his first-team debut in the First Division on 11 April 1999, keeping a clean sheet in the 0–0 East Anglia derby draw against rivals Ipswich Town at Carrow Road.

[citation needed] These man of the match displays included home fixtures with Derby County and Stoke City; he pulled off a save from Gerry Taggart during the latter.

[citation needed] Performances of this high standard led to his first England international call up for the friendly in March 2004 versus Sweden.

[citation needed] It proved to be Green's worst season as Norwich's number one, keeping just seven clean sheets in 42 league appearances.

[22] In 2008–09, Green saved yet another penalty, this time on 30 August 2008 against Jason Roberts of Blackburn Rovers, West Ham then went on to win the match 4–1.

[17] And again played in all 38 league matches for West Ham in 2009–10, keeping eight clean sheets and saving yet another penalty, this time from Aston Villa's Ashley Young in a 2–1 victory.

[25] On 19 March 2011, Green made a world-class save against Gareth Bale's free kick in the 0–0 draw with Tottenham Hotspur at White Hart Lane.

West Ham, who had not named a substitute goalkeeper in their squad for the match, were forced to play the remainder of the second-half with midfielder Henri Lansbury in goal.

[33] Green agreed terms with Queens Park Rangers (QPR) on 21 June 2012, and joined on a free transfer on 1 July, on a two-year contract.

[38] After the sacking of Hughes, new manager Harry Redknapp replaced Julio César with Green at half time during his first match in charge, against Sunderland on 27 November 2012.

[52] Earlier in the season, on 26 December, he saved an early penalty in an eventual 2–1 loss to Arsenal, as his teammate Eduardo Vargas pointed out which way fellow Chilean Alexis Sánchez was likely to shoot.

[55] On 7 August 2016, Green made his Leeds debut against QPR in a 3–0 defeat, in which he failed to punch a ball from a corner leading to a Sol Bamba own goal.

[60] After making his 600th league appearance, on 26 February 2017, Green saved a penalty from Sheffield Wednesday striker Jordan Rhodes in Leeds' 1–0 victory.

[64] After the signing of Andy Lonergan on 27 August 2017,[65] Leeds reached a mutual termination the same day with Green to allow him to move to Premier League side Huddersfield Town.

[68] Green signed for Premier League club Chelsea on 26 July 2018 on a one-year contract to provide cover for Thibaut Courtois (later sold and replaced by Kepa Arrizabalaga) and Willy Caballero.

[73] On 31 May 2005, he became the sixth Norwich player to wear the Three Lions shirt when he appeared as a half-time substitute for David James in a 3–2 friendly win against Colombia at Giants Stadium in the United States.

[87] Manager Fabio Capello opted not to name his first choice goalkeeper until the day of England's opening match, against the United States on 12 June, at which point he selected Green to start.

[88] With England leading 1–0 in the 40th minute, Green failed to save a long-range shot from U.S. midfielder Clint Dempsey, which bounced off his gloves and into the net.

[96][97] Green stated in an interview in 2017 that he was studying at the Open University for a BA Hons Business Management Degree in order to have something to focus on after he retires from football.