Foster dropped into non-league football to join Conference Premier club Dagenham & Redbridge in September 2004. He made a breakthrough into the first team squad during the second half of the 2004–05 season and signed a new three-year contract in February 2005. Foster was a regular during 2005–06 season and missed just one league match during 2006–07, in which the Daggers secured promotion to the Football League after winning the Conference Premier title. He signed a new two-year contract following the promotion. Foster continued to appear regularly for the club in League Two and made 69 league appearances and scoring three goals before being released at the end of the 2008–09 season. During five seasons at Victoria Road, Foster made 186 appearances and scored four goals.
On 17 June 2009, Foster and former Dagenham & Redbridge teammates Sam Saunders and Ben Strevens joined newly-promoted League One club Brentford on free transfers, with Foster signing a one-year contract. He made 42 appearances during the 2009–10 season, in which the Bees trod water in mid-table before a strong finish elevated the club to a 9th-place finish. He was given a free transfer at the end of the season.
Wycombe Wanderers
On 25 June 2010, Foster and former Brentford teammate Ben Strevens joined newly-relegated League Two club Wycombe Wanderers. He made 41 appearances and scored one goal during a successful 2010–11 season, in which the Chairboys secured an automatic return to League One after a third-place finish. Foster signed a new two-year contract in May 2011, but the Chairboys' return to League One was brief, with the club being relegated straight back to League Two at the end of the 2011–12 season. After overcoming a shoulder injury, Foster began the 2012–13 season as a regular, before suffering a season-ending knee injury late in a match versus Rotherham United on 20 November 2012. He underwent surgery in January 2013, but failed to recover before the end of the season. Despite being out of contract, Foster remained at Adams Park into the early months of the 2013–14 season, but was forced to retire from football in November 2013. In three seasons with Wycombe, he made 125 appearances and scored one goal.
International career
Foster won three caps for England at U16 and U18 level. He made two appearances in England C's victorious 2007 Four Nations Tournament campaign.
