He represented Alfreton Town, Barnsley, Cardiff City, Stoke City, Colchester United, Queens Park Rangers, Plymouth Argyle, Southend United, Hereford FC and Weston Super Mare and he was player-manager of Aldershot Town for three months in 2015.

[2] He began his professional career at Barnsley in 1999, winning the club's young player of the year award in his first full season.

[8] The move was not made permanent at the end of his loan spell, but he was regarded as a very popular and respected player with the fans at Layer Road.

[9] He signed for Championship rivals Plymouth Argyle on an emergency loan deal on 9 August 2008, allowing him to make his debut later that day against Wolverhampton Wanderers.

[11][12] On 5 August 2010, Barker joined Southend United on loan for one month after being told he was surplus to requirements by Argyle manager Peter Reid.

In October 2016, he joined National League South side Weston-super-Mare as player/assistant manager to boss Scott Bartlett.