Professor Murphy has taught at universities in Aix-en-Provence, London, Mexico City, Paris and Haifa, as well as in the United States. Additionally, he did administrative work with the Government of India as a fellow in the Afro-Asian Public Service Fellowship Program, which was a program sponsored by Syracuse University and the Ford Foundation.
Professor Murphy is involved with several professional organizations. He is the ABA's Alternate Observer at the United States Mission to the United Nations, was on the Council of the ABA's Section of International Law and Practice from 1994-96 and from 1999-2001 served as the Section’s International Legal Scholar, in which capacity he serves on the Section’s Council. In addition, he was on the Executive Council of the American Society of International Law from 1989-92 and is a honorary vice-president 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. Department of Justice; the United Nations Crime Prevention Unit, Vienna, Austria; the ABA Standing Committee on Law and National Security; the U.S. Department of State; the United Nations Association of the United States of America; the Commission on the Organization of the Government for the Conduct of Foreign Policy; the International Task Force on Prevention of Nuclear Terrorism; and University Microfilms International. He is a member of the Editorial Advisory Board of The International Lawyer. Professor Murphy was a Co-editor (w/Jay Vogelson) of the World Order Under Law Reporter.
He has written a number of books, 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); and Legal Aspects of International Terrorism: Summary Report of an International Conference (1980). He has also co-authored several books, including: The Constitutional Law of the European Union (1996 & Supp. 1999) (w/James D. Dinnage); Instructor's Manual for the Constitutional Law of the European Union (1996) (w/James D. Dinnage); Teacher's Guide for the Regulation of International Business and Economic Relations (1992); The Regulation of International Business and Economic Relations (1991) (w/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) (w/Alona E. Evans). Professor Murphy also has written many scholarly articles on the topics of international law and international terrorism.