Ms. O’Brien is currently the Ambassador of Ireland to France and to Monaco. From September 2013 to September 2017, she was the Ambassador of Ireland to the United Nations and other International Organisations in Geneva. From August 2008 to September 2013, she was The Legal Counsel and Under-Secretary-General for Legal Affairs of the United Nations.
She previously served as the Legal Adviser to the Department of Foreign Affairs of Ireland, Senior Legal Adviser to the Attorney General of Ireland and Ireland’s Legal Counsellor to the European Union in Brussels.
Earlier in her career, Ms. O’Brien practiced law at the Irish Bar and at the Bar of British Columbia, Canada. She held academic positions at the University of British Columbia, Canada.
Ms. O’Brien earned her law degrees in Trinity College, Dublin, the Kings Inns, Dublin, and the University of Ottawa, Canada. She is a member of the Irish Bar and of the Bar of England and Wales. She is a Fellow of the Society for Advanced Legal Studies, London and a Fellow of the Foreign Policy Association (US). She is Vice-President of the Dublin University Law Society, a Master of the Bench of the Middle Temple, London and an Honorary Bencher of the Kings Inns, Dublin. She was awarded an Honorary Doctorate in Laws by Trinity College, Dublin in April 2019.