An expert in regulation and governance, with a specialization in the legal regulation of charities, Professor Breen is a graduate of both UCD and Yale Law School. She teaches NGO Law & Governance and Equity and the Law of Trusts at UCD. A qualified barrister, she is the former President of the International Society for Third Sector Research (ISTR) and a member of the International Centre for Not-for-Profit Law’s International Advisory Council. In 2021 Oonagh was appointed as Chair of the Independent Review of Charity Regulation in Northern Ireland and oversaw the publication of the Review Panel’s Report in 2022.
A regular international speaker on comparative charity regulation matters, Oonagh has published extensively and is a co-editor (with Alison Dunn and Mark Sidel) of Regulatory Waves: Comparative Perspectives on State Regulation and Self-Regulation Policies in the Nonprofit Sector (Cambridge University Press, 2017), co-author of Law of Charities in Ireland with Philip A. Smith (Bloomsbury Professional, 2019) and co-editor with Noel McGrath of Palles: The Legal Legacy of the Last Lord Chief Baron (Four Courts Press, 2022). She has held both Fulbright and Government of Ireland Research Fellowships and has served as a Research Fellow at the Hauser Center for Nonprofit Organizations at Harvard University (2009), as an Ian Potter Foundation Fellow at ACPNS, Brisbane (2016) and as a Research Fellow at Carleton University, Ottawa (2025). Visiting appointments include De Paul Law School, Chicago, University Missouri Kansas City, University of California, Davis, Brooklyn Law School, Southern Illinois University and the University of Victoria, New Zealand. Oonagh was appointed as Commissioner in October 2025.