[8] He began his career at his home town club Barrow Raiders, and after 11-years at St. Helens, ended his playing days with a season loan move to the Hull Kingston Rovers.

Having won Super League VI, St. Helens contested the 2003 World Club Challenge against 2002 NRL Premiers, the Sydney Roosters.

St. Helens reached the 2006 Super League Grand final to be contested against Hull FC, and Gardner played on the wing and scored a try in Saints' 26–4 victory.

As 2006 Super League champions, St Helens faced 2006 NRL Premiers the Brisbane Broncos in the 2007 World Club Challenge.

Gardner was selected in June 2007 in a young Great Britain team named by new coach Tony Smith for their match against France at Headingley.

It had been Gardner's intention to play on till 2015, but accepted an offer to join Saints' backroom staff instead, as an Assistant Strength and Conditioning Coach.