Primarily a right-sided defender, Gunter made his senior debut for Cardiff on 22 August 2006 against Barnet in the League Cup first round, playing the full 90 minutes of a 2–0 loss at Ninian Park. After being included in the first team squad on several occasions, his league debut came in a 1–0 home loss to Queens Park Rangers on 17 November 2006. Gunter was praised for his performance by manager Dave Jones, who commented "Chris did the right things, let nobody down, and will only get stronger." Gunter would later describe his second league appearance, a 4–1 defeat to Hull City, as one of the lowest points of his career. However, he was able to maintain his place in the squad, competing with Kevin McNaughton and Kerrea Gilbert.