She is a member of Fine Gael, part of the European People's Party.
She previously served as Tánaiste from 2016 to 2017,
Minister for Business, Enterprise and Innovation from June 2017 to November 2017, Minister for Justice and Equality from 2014 to 2016, Minister for Children and Youth Affairs from 2011 to 2014, Leader of the Opposition in the Seanad and Leader of Fine Gael in the Seanad from 2007 to 2011.
She was a Teachta Dála (TD) from 1992 to 2002 and 2011 to 2019.
She was also a Senator for the Labour Panel from 2007 to 2011.She was the second Fine Gael politician to ever hold the office of Tánaiste, after Peter Barry in 1987.