He joined Sale Sharks in 2004. Foden’s desire to play scrum half saw him sign for Northampton Saints on the basis of a promise to play him at his preferred position; a promise that Sale Sharks could not give him, considering his strong performances at full-back, and the club presence of England international scrum-half Richard Wigglesworth and the arrival of Welsh international Dwayne Peel for the next season. In the 2005–2006 season, Foden played as a replacement in the final as Sale won their first ever Premiership title.

His career has been divided between playing at scrum-half and fullback, though he can also operate on the wing. In an interview in March 2009, Foden accepted that his future lay at playing fullback.

Foden was named in the England squad for the Six Nations on 14 January 2009, and earned his first cap for the England v Italy match on 7 February 2009 when he came on as a replacement at scrum-half for Harry Ellis, with England winning 36–11.

He was included in the England squad for the 2009 summer tour against the Barbarians and Argentina and made his first start for England in the uncapped game against the Barbarians on 30 May 2009, a game which saw him playing on the wing and scoring a try in the 32nd minute.

He was named in the elite player squad for the 2010–11 season. Later that year he cemented his place as England’s first-choice fullback, his early flirtation with scrum-half shelved after some strong form. Foden was a key member of the side that beat Australia twice in 2010 and also started all of England’s Six Nations games as they came up short of a Grand Slam in 2011. He gained more metres (100.6) in the 2011 6 Nations than any other player in the Championship. Foden was selected for England’s 2011 World Cup squad, holding off the challenge of Delon Armitage to retain the fullback shirt during England’s disappointing campaign.

In March 2011, following a Saints win over Wasps, Foden was arrested following an altercation with a taxi driver in London, but both Northampton and the RFU were happy to let the issue lie after he accepted a police caution.

Foden was married to Una Healy of British-Irish girl group, The Saturdays. They married on 30 June 2012 in her native Ireland. On 13 March 2012, Una gave birth to their daughter, Aoife Belle Foden. Una confirmed on her Instagram page in September 2014 that she and Foden were expecting their second child together, due in 2015. Their son Tadhg John Foden was born on 2 February 2015. In July 2018, it was announced that Foden and Healy had separated. Foden married Jackie Belanoff-Smith in 2019. On 20 May 2020, Jackie gave birth to their daughter Farrah.

In May 2014, Foden won the Aviva Premiership title with Northampton, playing 80 minutes plus extra time in the final against Saracens at full back and scoring a try.

After a decade with the club Northampton confirmed that Foden would be leaving at the end of the 2017/18 season. In July 2018, Rugby United New York announced that they had signed Foden for the 2019 Major League Rugby Season.

In October 2019, Foden was a contestant in The X Factor: Celebrity as a member of the group, Try Star, alongside Levi Davis and Thom Evans. They were eliminated in the semi-final, finishing in fifth place.