A deep-voiced performer, Kilgarriff began his career on stage in pantomime (in imposing roles such as giants and ogres, Aladdin's genie, and Little John), and music hall (often as Mr. Chairman, the master of ceremonies role). His television work dates to 1959, including the regular role of King Edward IV on The Golden Spur and appearances on the comedies Taxi! and Whack-O. He went on to appear several times in heavily costumed roles on Doctor Who, notably as the Cyber Controller in "Tomb of the Cybermen" and "Attack of the Cybermen" and the title character in "Robot." Other on-camera credits include the 1967 film of Camelot and an episode of UFO.