[1] He came through the youth system at Doncaster Rovers[3] and made his senior debut on 11 May 1991, in the starting eleven for the last Fourth Division match of the 1990–91 season, away to Gillingham.
Cullen turned professional in September 1991, and made a handful of first-team appearances in the first half of that season,[4] but dropped out of contention.
[4] In March 1997, Cullen returned to the Football League when Hartlepool United manager Mick Tait signed him from Morpeth for a fee of £1,000 and a significant sell-on clause.
The club could not risk rejecting the £250,000 fee, of which £75,000 had to go to Morpeth, because he would have been able to leave at the end of the season for free under the Bosman ruling.
[12] Cullen was released at the end of the 2001–02 season, during which he made 17 appearances, and he signed a one-month contract with Third Division Darlington.