Actor, theatre producer and television scriptwriter, Marcus Cooney was educated at St Virgil's College, Hobart, and at the University of Tasmania. His first career was in teaching and he spent some time employed by the Education Department on King Island. Cooney's theatrical career began in the late 1950s when he made his acting debut in the revue 'Fowl Play' (1959), produced by the University of Tasmania's Old Nick Company. The University newspaper Togatus commented on his performance as Eliza Doolittle which was 'one of the highlights'. Cooney maintained a long association with the Old Nick Company, of which he was a life member, both as an actor and producer, producing the 1963 revue 'Sin-til-Eight'.
In 1970 Cooney collaborated with Michael Boddy (q.v.), a friend from Old Nick Company days, and Ron Blair (q.v.) to write the knockabout socio-political satire, Biggles (q.v.) the first production staged by the Nimrod Theatre Company (Sydney). All three were involved the following year with another Nimrod success, Hamlet on Ice (q.v.). A satiric pantomime-style music theatre production, it also included contributions from Arne Neeme and songwriters Grahame Bond and Rory O'Donoghue (qq.v.). Among Cooney's other theatre works are Cash (q.v.), 1972), co-written with Michael Boddy and Between the Lines (q.v., 1978). In addition to his stage writing Cooney also wrote episodes for numerous television series. These have included Jackanory (1970), The Group (1971), Nice Day at the Office (1972), Prisoner (q.v., 1980) and A Country Practice (q.v., 1982-1983).