Halligan was born in Dublin in 1936. Educated at St James's Christian Brothers School and Kevin Street College of Technology, Dublin, his early career was as an economist. He worked with the Irish Sugar Company until 1967 when he became involved in politics. In that year he became General-Secretary of the Labour Party. The leader, Brendan Corish, relied on Halligan's intellectual and political skills in his new role. Under Halligan the party underwent an energetic reorganisation. New structures and policies were put in place, coinciding with the party's leftward policy shift and an acute anti-coalition stance. Halligan strongly supported both ideals, but was instrumental in securing the eventual, and somewhat unwilling, acceptance by the party of the reversal of anti-coalition stance after the disappointing results in the 1969 general election.
The 1973 general election resulted in a Fine Gael-Labour Party coalition government coming to power. Halligan, who did not contest the general election was rewarded by being appointed to Seanad Éireann. Three years later in 1976 he won a by-election in Dublin South–West, and as a result became a Teachta Dála (TD). After boundary changes, he stood in the new Dublin Finglas at the 1977 general election, but was not re-elected. He continued to serve as General-Secretary of the party until 1980. Halligan stood again in the revived Dublin North–West constituency at the 1981 and November 1982 general elections, but was not elected in either contest. However, he was appointed as a Member of the European Parliament (MEP) from 1983 until 1984, replacing Frank Cluskey.
Following the end of Halligan's political career he has been managing partner in a public affairs consultancy. He is Chairman of the Institute of International and European Affairs, a policy think tank and forum, and Adjunct Professor in European Affairs at the University of Limerick and was chairman of Bord na Móna from 1985 until 1995. He has been a non-executive member of the board of Irish Permanent since 1992. Like many of his colleagues in the Labour Party, Halligan has had a strong commitment to Europe and European affairs, a trait which was hidden during the party's campaign against the 1972 referendum deciding Ireland's membership of the European Economic Community. Halligan has also been a member of the Irish Council of the European Movement.
He represented cigarette manufacturers throughout the 1990s, heading the campaign to limit tax increases and opposing restrictions on advertising.
He is currently the Policy Coordinator for the Labour Party.
- "Mr. Brendan Halligan". Oireachtas Members Database. Retrieved 1 December 2012.
- "Brendan Halligan". ElectionsIreland.org. Retrieved 11 February 2008.
- "Adviser denies leaving campaign due to tobacco links". Irish Independent. 10 October 2011.