Cardiff City
On 4 June 2009 he signed for Football League Championship side Cardiff City on a three-year contract for a fee of around £300,000, describing the transfer as his "ideal move". He made his debut for the club in a 4–0 win over Scunthorpe United, the first competitive match at the Cardiff City Stadium. On 17 August 2010, it was revealed that Motherwell were still owed around £175,000 of the transfer fee and that no further payments had been made toward the fee since January 2010. However, the following week Cardiff reached an agreement with Motherwell and £100,000 of the remaining fee was paid. Quinn scored his first Cardiff goal on 2 April 2011, in a 4–1 win over Derby County.
Quinn was named captain for the League Cup game against Oxford United. and again for Huddersfield Town. He got his first league appearance off the season against Southampton, on 28 September, following a knock to Kevin McNaughton in the game. After only four starts during the season, Quinn was released at the end of his contract.