Kielty began performing regularly while a pupil at St Patrick's Grammar School, Downpatrick. Kielty was persuaded to take part by a Games master who spotted his impersonations of local politicians, celebrities, and sportsmen. His professional career started while he was still a psychology student at Queen's University, Belfast, appearing in a show called "The Empire Laughs Back", a show staged in The Empire Music Hall on Botanic Avenue in Belfast, started by him and fellow student Jackie Hamilton, who went on to become a BBC producer. One routine performed at local gigs involved donning a balaclava and making spoof paramilitary pronouncements.