Having been developed as a player through Dundee United's youth scheme, Walker made six appearances for the United first team, his last coming in September 1997. In December 1998, he joined St Mirren but would make just one substitute league appearance before joining Stranraer three months later. His stay at Stair Park lasted two-and-a-half years, where he managed 14 goals from 61 league appearances; his stay included a short loan spell with Queens Park. In 2001, he headed to Partick Thistle, where he spent two seasons, before a similar time with Greenock Morton. A year at Stranraer followed, before a short-lived spell at Montrose. Walker signed for Ayr United in August 2006 before joining East Fife at the start of the 2007-08 season. After playing just once in the 2008-09 season, Walker moved to Irvine Meadow.