Oonagh B. Breen graduated from University College Dublin with first class honours (BCL, 1992, LL. M., 1995). A Tutorial Scholar (1992), she was appointed lecturer in 1994, and was called to the Irish Bar in 1997. Graduating second in her class, she was awarded the Society's Exhibition Prize and a Bar Council Bursary. She became a Senior Lecturer in 2008.

In 2003, Dr. Breen was awarded a Fulbright Scholarship and was made a Government of Ireland Research Fellow. She commenced studies at Yale Law School in that year as a Lillian Goldman Scholar. In 2004, she obtained her LL. M. from Yale and in 2006 she was awarded her J.S.D. for her doctoral dissertation on comparative perspectives on the legal regulation of charities and the role of state-nonprofit partnership in public policy development. From 2004 to 2006, she was the recipient of the National University of Ireland's Travelling Studentship award. She was a visiting professor at De Paul Law School, Chicago in 2002, at University Missouri Kansas City Law School in 2004 and at University of California, Davis in 2008. She has been the external examiner in Equity for the Law Society Final Examinations Part 1 since 2001. In 2009, Oonagh was a visiting Research Fellow at the Hauser Center for Nonprofit Organizations, Harvard University.

Dr Breen specialises in the area of comparative charity regulation and nonprofit-state collaboration in public policy formation and development. A co-author of the Law Society's Report, Charity Law: The case for reform (2002), she was appointed by the Department of Community Rural and Gaeltacht Affairs to write an external report on the submissions received during the Department's charity law reform consultation process in 2004. She has worked with nonprofit representatives, the Law Reform Commission and the Irish Government on issues relating to the reform of charity law. Since 2005 she is the Irish rapporteur for the United States International Grantmaking Project, which facilitates international grantmaking by US foundations. In 2006, she was named as an emerging scholar by ARNOVA.In 2007 she was awarded a University President's Award for Teaching & Learning and in 2008, Dr. Breen was awarded a Distinguished Research Award by ICNL/CORDAID for her work on European regulation of nonprofit entities. Oonagh is a frequent contributor at international conferences and colloquia on the topic of charity law reform and has published extensively in this area.

Oonagh is interested in hearing from prospective PhD students in the areas of comparative charity law and regulation, nonprofit governance and the broader areas of equity and the law of trusts.