Declan graduated from Ireland's National Film School in 1989 with the award-winning short film Big Swinger, and has since gone on to direct some of the top rated shows on Irish television, including Any Time Now, The Clinic and the award winning Pure Mule, which won five IFTAs including Best Director.
In 1992, he set up Paradox Pictures with fellow graduate Liam O'Neill. The company produced several feature films including Separation Anxiety and How Harry Became a Tree. During that time Declan directed the award winning shorts Quando and Sunny's Deliverance.
In 2008, Declan released his first feature film, Eden, adapted by Eugene O'Brien from his play of the same name. Starring Eileen Quinn, who won Best Actress at the Tribeca Film Festival for her role, Eden tells the story of a marriage falling apart and was nominated for a host of awards, including the European Academy Film Awards and for IFTA Best Director 2009.
Most recently Declan has directed the series, Scúp, for TG4 and BBCNI written by Colin Bateman.