Her educational background includes a Ph.D. (under special regulations) and an LL.B. (Masters of Law, 1st class honors) from Cambridge University, England. A J.D. (multiple honors) from the Columbia University School of Law, New York. An MSc. (Masters of Science) in International Relations from the London School of Economics, England.
And a B.A. (summa cum laude, Phi Beta Kappa, History Honors) from Northwestern University, Illinois.
Since joining the Notre Dame Law School in 2005, she has taught the courses International Law, International Law and the Use of Force, International Dispute Resolution, International Environmental Law, International Art Law, and Contracts. Prior to joining Notre Dame's faculty, she taught at The Ohio State University (1999–2005), as the William B. Saxbe Designated Professor of Law in the Moritz College of Law and was a Senior Fellow of the Mershon Center for the Study of International Security and Public Policy. She was also a Visiting Professor at the University of Cincinnati College of Law (1998–1999).
Prior to beginning her career in academia, she practiced law as an Attorney Associate with Covington & Burling in Washington, D.C. (1985–1988). During the 2014–2015 academic year, O'Connell served as the Senior Templeton Foundation Legal Scholar at the Center of Theological Inquiry/Law and Public Affairs (Princeton).
Among her many grants, awards, and recognitions are a British Marshall Scholarship, a German Humboldt Foundation Fellowship, a Lauterpacht Research Centre for International Law (Cambridge)/MacArthur Foundation Fellowship, a U.S. Army Certificate of Achievement, funding from the Mershon Center (OSU) and the Kroc Institute (ND) for an international/inter-disciplinary conference "What is War?" In 2015, she was presented with the University of Notre Dame's Reinhold Niebuhr Award, which honors a person whose life and writing promote or exemplify the area of social justice.
O'Connell is a member of and former Vice President of the American Society of International Law, a fellow of the Center for Theological Inquiry (Princeton Theological Seminary), and a member of the German Society of International Law, the International Institute for Humanitarian Law (San Remo, Italy), the International Law Association, and the American Branch of the International Law Association.
