Ms Breen is recognized for her expertise in charity law, governance and regulation and teaches both in this field and in equity and the law of trusts. A graduate of University College Dublin (BCL 1992, LLM (by research) 1995) and of Yale Law School (LLM 2004, JSD 2006), where her doctoral work focused on comparative perspectives on the legal regulation of charities and the role of state-nonprofit partnership in public policy development, she was called to the Bar of Ireland in 1997.