Cultured defender Simon King began his career as a left-back with his home-town club Oxford United and has also been capped internationally by the England C team.

He was Gillingham's biggest signing during the summer of 2007 costing £200,000 from Barnet.  King scored seven goals in 167 appearances at Underhill and was voted Player of the Year for the 2006/07 season.

He made his debut for the Gills in the season opening away defeat at Cheltenham Town and was a permanent fixture in the side clocking up 42 League appearances. He rounded off his debut season for Gillingham by winning the Players Player Of The Year and Away Player Of The Year awards

2008/09 was an even better season for the central defender who was a virtual ever present as the Gills secured promotion back to League One at the first attempt. Simon dominated the club's end of season awards clinching the Player of the Year, Players Player, Supporters Player and Away Supporters Player of the Year trophies.

In the summer of 2009 he committed his long term future to Gillingham by agreeing a new three year contract but missed the entire 2009/10 campaign after damaging ankle ligaments in a pre-season friendly at Bromley.