Born in Amherst, Ohio, Richard B. Lillich received his bachelor's degree from Oberlin College in 1954; his LL.B from Cornell Law School in 1957, with a specialization in International Affairs; and his LL.M and J.S.D from New York University School of Law in 1959-60, with a specialization in International Law. Lillich was admitted to the New York Bar in 1957. He practiced private law until 1960 and then joined Syracuse University College of Law where he was a professor and director of International Legal Studies until 1969. In 1963 and 1966-67 he was a Ford Foundation Fellow and a Guggenheim Fellow in England. He came to the University of Virginia that same year and was named Howard W. Smith Professor in 1977. In 1994 he was named Visiting Edward Ball Eminent Scholar Chair in International Law at Florida State University College of Law. He held both of these positions until his death in 1996. In addition he was a visiting professor or fellow at many prestigious institutions, including the United States Naval War College; the Centre for International Studies, Cambridge, England; New York University School of Law; All Souls College, Oxford, England; the Max-Planck Institute, Heidelberg, Germany; University of Georgia School of Law; and St. Louis University School of Law.

A prominent scholar of international law, Lillich published more than 30 books and scores of articles. He taught courses in International law, admiralty, and human rights. He became respected scholar in the fields of international claims, international investment law, diplomatic protection of aliens and their property, state responsibility, and international humanitarian and human rights law. He was a longtime, active leader in the American Society of International Law and served for many years on the editorial board of the American Journal of International Law. From 1973-85 he edited the Virginia Legal Studies series. He was co-founder and President of the Procedural Aspects of International Law Institute, a group of international law scholars and practitioners he helped establish in 1965. Other memberships include the American Law Institute, the Association of the Bar of the City of New York, the British Institute of International and Comparative Law, the International Law Association. As an active lawyer preoccupied with human rights problems worldwide, he served on the advisory boards of a number of international groups focusing on these problems, including the International Human Rights Law Group, which he helped to found in 1978; the Advisory Council of the U.S. Institute of Human Rights; and the Advisory Board of the Urban Morgan Institute of Human Rights. His national service included consultation for the U. S. Naval War College, Department of State, the U.S. Centre Against Apartheid, and the Department of State in the Iran-United States Claims Tribunal.