Elected to the Dundrum Ward of Dún Laoghaire-Rathdown County Council in 2014, Martin is the deputy Green Party leader and education spokeswoman. For the last 15 years, she has been a teacher of english and music at St Tiernan's Community School in Dundrum. She joined the Green Party in 2007, weeks after the birth of her first child an now has three children. Her husband, Cllr Francis Duffy, also is a member of the Green Party and is currently deputy mayor of South Dublin County Council. She was a first time general election candidate and while she achieved an strong 10 per cent of the vote on first preferences, it was her impressive ability to attract transfers which brought her over the line, particularly from eliminated female candidates, Sorcha Nic Cormaic of Sinn Féin and Fianna Fáil's Mary White. She was the first Green candidate elected to the 32nd Dáil.