Professor Murphy received his B.A. from Cornell University in 1959 and his LL.B. with Specialization in International Affairs from Cornell University in 1962. After his graduation from law school, from 1962-1963, Professor Murphy worked with the Indian Government as a Fellow in the Afro-Asia Public Service Fellowship Program, which was a program sponsored by Syracuse University and the Ford Foundation. After his return to the United States, he worked as an associate with a Wall Street law firm for a year and then joined the Office of the Legal Advisor, U.S. Department of State, where he served from 1964-1967 in the Office of the Assistant Legal Advisor for United Nations Affairs. From 1967 to 1969 he worked as an associate with a law firm in Washington D.C. and then began his teaching career in September 1969 at the University of Kansas School of Law.
Professor Murphy has taught in Aix-en-Provence, London, Mexico City, Paris and Haifa, as well as at Cornell, Georgetown, and Kansas Universities. From 1980-81, he was the Charles H. Stockton Professor of International Law at the Naval War College in Newport, Rhode Island.
Professor Murphy has been active in several professional organizations. For the ABA he served as its Alternate Observer at the United States Mission to the United Nations, was on the Council of the ABA's Section of International Law, was the Section's International Legal Scholar, and currently is a member of the ABA's Francis Shattack Security & Peace Initiative. For the American Society of International Law, he has served on the Society's Executive Council and on its Board of Review and Development, as well as in a variety of other capacities. He is currently an Honorary Vice-President and Patron of the American Branch of the International Law Association. He has served as consultant to the Council for International Exchange of Scholars; the U.S. Departments of Justice and State; the United Nations Crime Prevention Unit, Vienna, Austria; the ABA Standing Committee on Law and National Security; the United Nations Association of the United States of America; the Commission on the Organization of the Government for the Conduct of Foreign Policy; and the International Task Force on Prevention of Nuclear Terrorism. He currently is a member of the Editorial Advisory Board of The International Lawyer and previously served on the Editorial Boards of Terrorism and Political Violence and Transnational Publishers. He was a co-editor (with Jay Vogelsong) of the ABA's World Order Under Law Reporter.
He has written a number of books and monographs, including Report of the Task Force on an International Criminal Court of the American Bar Association (1995); State Support of International Terrorism: Legal, Political, and Economic Dimensions (1989); Punishing International Terrorists: The Legal Framework for Policy Initiatives (1985) ;The United Nations and the Control of International Violence: A Legal and Political Analysis (1983); Legal Aspects of International Terrorism: A Summary Report of an International Conference (1980); The United States and the Rule of Law in International Affairs (2004); and The Evolving Dimensions of International Law: Hard Choices for the World Community (2010). He also has co-authored several books, including : The Constitutional Law of the European Union (1996, Supp. 1999, and 2nd edition 2008) (with James Dinnage); The Regulation of International Business and Economic Relations (1991) (with the late Alan C. Swan) (for which he was awarded a Certificate of Merit by the American Society of International Law), as well as a second edition of The Regulation of International Business and Economic Relations, published in 1999; and was co-editor and contributor to Legal Aspects of International Terrorism (1978) (with Alona E. Evans). Professor Murphy also has written many scholarly articles and reviews on the topics of international law and international terrorism.
On April 8, 2011, Professor Murphy became the recipient of the 2011 Louis B. Sohn Award for Public International Law, in honor of the late Louis B. Sohn, a distinguished international lawyer and scholar. The Section of International Law of the American Bar Association periodically presents the award to those persons who have made “distinguished, long-lasting contributions to the field of public international law.”