Errol O'Neill studied philosophy and theology in Rome before doing a Bachelor of Arts with a drama specialisation at the University of Queensland. He lived through the student movement with its New Left orientation in the 1960s. Since the early 1970s, he has been an actor, writer, director, dramaturg and producer, specialising in the creation of new work for the theatre and publicly identifying as a Marxist in the theatre industry. O'Neill was an actor, then resident writer-director with the Brisbane-based Popular Theatre Troupe (1977-82), where he performed in, wrote and directed many political satires which toured throughout Queensland and nationally. After it disbanded he wrote a trilogy of plays about the history of the labour movement: On The Whipping Side (1991), Faces in the Street (1983) and Popular Front (1986).
Highlights from O'Neill's career as an actor include three productions of Ron Blair's TheChristian Brothers, Jack Hibberd's A Stretch of the Imagination (La Boite, 1983), two productions of David Williamson's The Removalists (TN! 1985 directed by Bryan Nason, and La Boite 2003 directed by Lewis Jones), and two productions of the Futcher-Howard play A Beautiful Life (La Boite/Matrix/Brisbane Festival/Performing Lines). As well as with Queensland theatre companies, O'Neill has performed with the Melbourne Theatre Company, the State Theatre Company of South Australia, the Riverina Theatre Company and the Black Swan in Western Australia. His film credits include: The Delinquents (1988), Mr Reliable (1996), Joey (1997) and Crooked Business (2008). He has also appeared in episodes of such series as Mission Impossible (1988), All Saints (2000) and East of Everything (2008-09).
From 1984 to 1987 O'Neill was a member of the Australia Council and he served on Literature Board grant committees in 1990 and 1999. He has been a member of the Actors Equity Queensland Management Committee and the Queensland Branch of the Australian Writers Guild. In 2003 O'Neill was awarded a Centenary Medal for service to the arts and the entertainment industry, and the Alan Edwards Lifetime Achievement Award from the Actors' and Entertainers' Benevolent Fund (Queensland).
O'Neill has written for radio and acted in radio, television, film and video. He has published many short stories, written chapters and articles for various books and journals on aspects of theatre and society, and been a guest lecturer in tertiary drama courses. He was the brother of Dan O'Neill.
(Source: Errol O'Neill, 'Working As A Marxist In The Australian Theatre Industry', The Point OfChange : Marxism/Australia/history/theory, ed. Carole Ferrier and Rebecca Pelan (1998) 151-160; 'Errol O'Neill' in Errol O'Neill The Mayne Inheritance : a play (2004): 12.)