She was a leading Women's Rights campaigner in the 1970s when she was part of the Irish Women's Liberation Movement, from which she resigned due to differences in 1971. Fennell was involved in setting up the first refuge for "battered women" in Dublin. She was elected at the 1981 general election to the 22nd Dáil, as TD for Dublin South. After the election, Fine Gael entered into a coalition government with the Labour Party, and Fennell was a prominent backbencher.
Fianna Fáil regained power briefly at the February 1982 election, but the coalition was returned to power later that year at the November 1982 election and Fennell was appointed Minister of State at the Department of the Taoiseach (with responsibilities for Women's Affairs and Family Law) and Minister of State at the Department of Justice.
She lost her seat at the 1987 general election, and was nominated by the Taoiseach Garret FitzGerald to the 17th Seanad, in its last days. She was then elected to the 18th Seanad on the Labour Panel. At the 1989 general election, she was returned to the 26th Dáil, but retired from politics at the 1992 general election. She is survived by her husband Brian, and her three children.
- "Former minister Nuala Fennell dies". RTÉ News. 11 August 2009. Retrieved 11 August 2009.
- Fennell, Nuala (2002). "Irish Women's Liberation Movement". The Field Day Anthology of Irish Writing. 5. New York University Press. p. 202. ISBN 0814799078.
- Stephen Collins (11 August 2009). "Former minister Nuala Fennell dies". The Irish Times. Retrieved 11 August 2009.
- "Nuala Fennell". Oireachtas Members Database. Retrieved 12 August 2009.
- "Nuala Fennell". ElectionsIreland.org. Retrieved 12 August 2009.
- Fennell, Nuala: Nuala Fennell:political woman:a memoir, Dublin, Currach Press, 2009.