LeRoy Walters was born in Illinois and spent his elementary and secondary school years in Pennsylvania. He attended a small Pennsylvania liberal-arts college, Messiah College, receiving his B.A. in 1962.

After finishing a B.D. degree at the Associated Mennonite Seminaries in 1965, LeRoy studied for two years in Germany, one year at the University of Heidelberg and one year at the Free University of Berlin. While in Berlin, he also helped to organize East-West conferences in East Berlin, the German Democratic Republic, Czechoslovakia, and Poland.

In 1967 LeRoy returned to the United States and began a Ph.D. program in the Department of Religious Studies at Yale University. He finished his Ph.D. in Christian ethics in the spring of 1971, writing his dissertation on the topic "Five Classic Just-War Theories: A Study in the Thought of Thomas Aquinas, Vitoria, Suarez, Gentili, and Grotius." His dissertation received the Theron Rockwell Field Prize from the university.

During the summer of 1971, LeRoy joined the newly-established Joseph and Rose Kennedy Institute of Ethics and its Director, Andre Hellegers, as the first faculty member appointed to a multi-year term. He has remained a member of the Kennedy Institute since 1971. In 1975, LeRoy received an appointment as Assistant Professor of Philosophy. He was promoted to the rank of Associate Professor in 1980 and the rank of Professor in 1993. In the latter year he was also named the Joseph P. Kennedy, Sr. Professor of Christian Ethics at the Kennedy Institute. During the summer of 1996 LeRoy accepted a three-year term as Director of the Kennedy Institute. He served as director through June 2000.

Since 1975 LeRoy has been the editor and co-editor (with Joy Kahn and Doris Mueller Goldstein) of the annual Bibliography of Bioethics (35 volumes to date). He is also co-editor (with Tom L. Beauchamp, Jeffrey P. Kahn, and Anna C. Mastroianni) of an anthology entitled Contemporary Issues in Bioethics (7th ed., Wadsworth, 2008). In late 1994 LeRoy and co-author Julie Gage Palmer published a book entitled The Ethics of Human Gene Therapy (Oxford University Press, 1997).

Much of LeRoy’s research has been devoted to ethical issues in human genetics. In the past he taught courses on "Ethics and Human Genetics" and "Eugenics and Ethics." He also served for three terms on the Recombinant DNA Advisory Committee of the National Institutes of Health. From 1993 through 1996 he served as Chair of the committee, which reviews human-gene-therapy protocols.

Since 2003, LeRoy has devoted major attention to Holocaust Studies and to the "euthanasia" program initiated in 1939 under National Socialism. He has conducted detailed research on one major opponent of "euthanasia," asylum director Paul Gerhard Braune. He also does research on the life and thought of German theologian Dietrich Bonhoeffer.

A continuing interest in LeRoy’s work has been the development of a bioethics library. The Kennedy Institute library, now called the National Reference Center for Bioethics Literature, is the largest collection of materials on biomedical ethics under one roof in the world. Since 1973, the library has been ably led by LeRoy’s colleague, Doris Goldstein.

LeRoy is married and has two children, David and Robert. His first wife, Jane Martin Walters, died in 1988 after open heart surgery. In 1990 LeRoy married Sue Meinke Walters.