Born in Warrington, Cheshire, Foster signed for local club Crewe Alexandra as a trainee in August 1997 and made his debut on the 22nd of that month in Crewe's 1–0 loss to Bury. He made a second appearance in the same season a months later in Crewe's 1–1 draw with Bristol City. Foster however did not play any first team games for Crewe during the next season. A season on and Foster scored his first goal for Crewe in their 2–2 draw with Bury, the goal came in the 84th minute, Mark Rivers scoring the other goal for Crewe two minutes after Foster's goal. It took four seasons before Foster was received his first red card, which he received in Crewe's 2–1 loss at Gresty Road against Oldham Athletic. After Crewe's relegation from The Championship in the 2005–06 season, Foster, who was out of contract, decided to turn down a new offer by Crewe in favour of joining Championship side Burnley on a free transfer. He spent his first season at Burnley mainly as a squad player or substitute and started the 2007–08 season in similar vein. In August 2007 Foster was transferred to Barnsley for the sum of £100,000 where he signed a two-year contract. He was a long term target for Barnsley and they had been trying to sign the player throughout the summer. Foster made a positive start to his Barnsley career, enjoying a regular run in the team at right-back. Since his signing, Foster became a valued member of the Barnsley first team squad. His time at Barnsley so far has had one notable setback which came in the form of a sending off for two bookable offences during the 3–3 draw between Barnsley and Stoke at Oakwell on Boxing Day 2007. Two major high points have come in the FA Cup for Foster with him grabbing an equaliser for Barnsley twice in three separate games. First of all came a back heeled goal against Blackpool at Oakwell in the 3rd round, and secondly came a headed goal from Martin Devaney's cross against Liverpool at Anfield in a 5th round match that Barnsley went on to win 2–1. He bagged his first league goal for Barnsley at Watford in a 3–0 win, heading home Diego León's corner. Foster was named Barnsley's player of the season in his first year at the club. This honour was voted for by the fans, he beat club captain, Brian Howard, and winger, Jamal Campbell-Ryce into second and third place respectively. At the start of the 2010/11 season, the captaincy was passed to new signing Jason Shackell, to enable Foster to concentrate on his own game. Defender Stephen Foster joined Tranmere in June on a two-year deal, but Rovers have confirmed that player and club have already agreed to part company. The 32-year-old's contract has been terminated by mutual consent.
