[4] Family planning was deeply controversial in Ireland from the 1970s to the 1990s, particularly in Limerick, where Kemmy had lost his Dáil seat at the November 1982 general election, after being denounced by the Catholic Church for his opposition to the Eighth Amendment of the Constitution.

[4] At the 1992 general election, as the running-mate Jim Kemmy, she narrowly missed winning a second seat for Labour in Limerick East.

Her religion twice became an issue in 1994, when she was prevented from opening a Christian Brothers School and from reading a lesson at a mass for Limerick's civic week.

O'Sullivan was unsuccessful again at the 1997 general election,[6] but after Kemmy's death in September 1997, she was selected as the Labour Party candidate for the by-election in March 1998.

Eamon Gilmore was elected unopposed as leader,[8] O'Sullivan stood for the deputy leadership, and was defeated by Dublin West TD Joan Burton, by 1,480 votes to 1,276.

[11] On 20 December 2011, she was appointed Minister of State at the Department of Environment, Community and Local Government with special responsibility for Housing and Planning.

[17] In March 2015, the government, with O'Sullivan the minister responsible, confirmed it would lock away for 75 years any statements it received from victims of child sexual abuse (almost twice the normal length).