Folan began his career as a trainee at hometown club Leeds United, but did not make it to the first team. He made his professional debut with Rushden & Diamonds, playing 7 games on loan in the early part of the 2001/02 season. Shortly after, he joined Hull City on loan, but played just 22 minutes in one substitute appearance under Brian Little.
He signed for Chesterfield in 2003 on a free transfer. He scored 16 goals for the Spireites, 12 of which were in League One last season before a £500,000 January move to Wigan. He started 8 Premiership games, came off the bench a further 5 times, and scored twice.
This season he started the opening day game at Everton, was a used sub a week later against Sunderland, and made his final appearance in Tuesday's Carling Cup defeat to the Tigers.
He has signed a three-year contract with City and could make his debut at Blackpool on Monday.