Gardner signed a four-and-a-half-year contract with Birmingham City on 26 January 2010 for a fee reported as £3m plus £500,000 in add-ons. He made his debut on 7 February as a 68th-minute substitute, and set up the first of Kevin Phillips' goals as Birmingham came back to beat Midlands rivals Wolverhampton Wanderers 2–1. He scored his first goal for the club against Everton on 13 March. Towards the end of the season Gardner was preferred to Sebastian Larsson on the right of midfield. Restored to his favoured central position, he scored twice in the first home game of the 2010–11 season as Birmingham came from behind to beat Blackburn Rovers 2–1, and scored again in the next game away at Bolton Wanderers. Gardner's winning goal in extra time against West Ham United took Birmingham City through to the 2011 Football League Cup Final, and he was in the starting eleven as Birmingham won their first major trophy since 1963. He was the team's top scorer in the 2010–11 season with eight League goals, ten in all competitions, as Birmingham were relegated to the Championship.