Professor O'Brien is a specialist in the dynamics of financial regulation, with particular reference to capital market governance. He has written extensively on the intersection between regulatory form and ethical considerations. He is the recipient of a range of major grants from the Australian Research Council and the Economic and Social Research Council in the United Kingdom.
He is the author of a trilogy of books on regulatory politics: Wall Street on Trial (2003); Redesigning Financial Regulation (2007); and Engineering a Financial Bloodbath (2009). In addition he has edited a series of collections on corporate governance, including Governing the Corporation (2005); Private Equity, Corporate Governance and the Dynamics of Capital Market Governance and Corporate Business Responsibilities (2009). He is co-editor (along with Iain MacNeil of the University of Glasgow) of a major volume on the legal, policy and regulatory implications of the Global Financial Crisis, The Future of Financial Regulation (2010).
Professor O'Brien has held appointments at Queen's University, Belfast, Charles Sturt University and Queensland University of Technology. He has been affiliated to the Center for the Study of Law and Society at the University of California, Berkeley as a Visiting Scholar and at the University of Glasgow, where he was Visiting Professor of Financial Regulation and Policy. He is an Adjunct Professor at the Australian National University division of the Centre for Applied Philosophy and Public Ethics.
Prior to taking up a career in academia Professor O'Brien was an investigative journalist for a range of national and international broadcasters, including three divisions of the British Broadcasting Corporation - Network News and Current Affairs, BBC Northern Ireland and BBC World Service. He was also Editor, Television Current Affairs at Ulster Television in Belfast. He is a regular commentator on financial regulation to the national and international media and writes regularly for the Irish Times and the Australian Financial Review.