He first started acting in theatre, performing in Hamlet, The MadMan and the Nun, A Midsummer Night's Dream and The Hollow in the Sand. Delaney soon added screen acting to his resume, starring in the 2003 short film An Cuainín, and in 2005 appearing in the Irish television series Pure Mule and The Clinic. He went on to play the lead in the RTÉ series Legend.