- Cormac was also occasionally used as a pseudonym by Ernest Forbes in the 1920s
Orinally from Ardoyne in north Belfast, he was part of a Trotskyite faction that held national liberation to be more important than class struggle, and expressed these beliefs in his cartooning. He was part of the nascent small press in the 1970s, publishing ten issues of Resistance Comics between 1975 and 1978, which included surreal strips influenced by the American underground as well as political material. He caricatured himself as Paddy O'Looney of the "Irish section of the sixth intergalactic revolutionary movement". Other characters included Red Biddy, "the scourge of Irish male chauvinism". He also contributed to the Belfast People's Comic in 1977.
His weekly "Notes" ran in Republican News, a weekly paper published by the Belfast brigade of the provisional IRA and edited by Danny Morrison, from 1976, and in the national Sinn Féin paper An Phoblacht after Republican News merged into it in 1979, until 2004. His cartoons generally supported the faction led by Gerry Adams that came to control Sinn Féin and the IRA, and often supported IRA violence, earning condemnation from The Guardian and Tim Pat Coogan, although he could on occasion empathise with the ordinary British soldier on patrol.
He had a regular strip, "Bad Taste", in the British weekly Socialist Challenge in the 1970s, followed by "A Piece of the Action" in its successor Socialist Action in the 80s. He also scripted an anti-clerical strip, "Dog Collars", drawn by Ian Knox and signed "Kormski", in Fortnight magazine in the 80s'.
A self-taught guitarist, he played, sang and wrote songs for the Men of No Property from the early 70s. As a dramatist, he wrote the radio play Gibraltar, about the killing of IRA activists by the SAS there in 1988, Paddy on the Road (2002), a monologue about singer Christy Moore starring Terry O'Neill, Black Taxis, and two musical comedies, The Session (2005) and The Ballad of Malachy Mulligan (2006).
He was married to Sandra from 1972 to 1984, and they had a son, Cormac. He died after a short bout with cancer on 12 March 2011, leaving a partner, Máire O'Hare.
- Cormac Strikes Back (1982)
- The Comic Book of MI5 (with Patrick Fitzgerald) (1987)
- The Peace Process According to Cormac (2005)
- Cormac Strikes Back: Resistance Cartoons from the North of Ireland, Information on Ireland, 1982
- RIP 'Cormac' - Brian Moore - cartoonist with An Phoblacht/Republican News, An Phoblacht, 13 March 2011
- Brian Moore RIP, The Broken Elbow, 28 March 2011
- Danny Morrison, Sudden Death of Brian Moore, 14 March 2011
- Cormac... An Phoblacht cartoonist, The Cedar Lounge Revolution, 14 March 2011
- Cormac Moore, Brian Moore, alias Cormac (14.9.1946 - 12.3.2011), 1 April 2011
- John Gray, Obituary: Brian Moore, 1946-2011, Culture Northern Ireland, 18 April 2011