Following a degree in European Studies at the University of Limerick, Mary joined the Irish Civil Service in 1978. Prior to her retirement in 2018, She was a member of the Management Boards of the Departments of the Taoiseach, Health and Children and Education and Skills. She was also a member of a wide range of national bodies including National Statistics Board, the National Economic and Social Council and the Board of Science Foundation Ireland with a particular interest in research for public policy.

She holds as Masters degree in Public Service Management from Trinity College, 2002.

Since retirement, she has continued to be active in the area of evidence for policy. She was a Visiting Fellow in Public Policy at the Long Room Hub Arts and Humanities Institute in Trinity College from 2018 to 2022 where she published, in particular, on the potential for strengthening the national architecture between the Irish policymaking and the Irish research systems.

She is currently a Visiting Scholar in the School of History, Anthropology, Philosophy and Politics at Queens University Belfast.

She is also a member of the Board of The Wheel – the umbrella organization for the Community and Voluntary Sector – and chairs the advisory board for the Early Learning Initiative in the National College of Ireland.

In 2021, she became a Member of the Royal Irish Academy was elected as Secretary for Policy and International Affairs at the Academy in 2024.