|Warren started his career at Chelsea but never made it into the first team, and instead was loaned out several times: Bournemouth 2000–01, West Bromwich Albion 2000–01 and 2001–02, and Dundee United in 2002–03.
Following his return from Dundee United, Warren was again loaned to Bournemouth, for a three-month spell, before signing a permanent deal with the club.He went on to make 23 appearances for The Cherries in that season, helping them win promotion via the playoffs. In the following season he established himself as a first team player, making 46 appearances in total and scoring 2 goals.
The 2004–05 season brought a playoff push with Warren playing an important part and scoring 3 goals. However, during an away derby with Swindon Town in March 2005, he suffered a double broken leg in a crunch tackle. Nonetheless, Warren signed a new deal with Bournemouth in the summer of 2006. He made his league return as a late substitute in the 3–0 defeat to Chesterfield at the start of the2006–07 campaign. In June 2007 Warren signed a new two-year deal with Bournemouth.
On 29 June 2012 it was announced that he has signed with League Two club AFC Wimbledon. He played a total of 9 league games for the Dons before being released from the club on 10 July 2013. On 16 August 2013, Warren joined Southern League Premier Division side Poole Town before joining the Hawks in November 2013. Last season he became a regular in the side, and has clocked up 54 games overall so far.