John is a member of the Order of Friar Servants of Mary (Servites) and was ordained at the University of St. Mary of the Lake. One of the founding faculty members of CTU, he served on the faculty from 1968 until his retirement in 2017.

John has been an active participant in the Christian-Jewish Dialogue as well as the wider interreligious dialogue for nearly fifty years He served for six years as President of the International Council of Christians and Jews and has served several terms on the board of the Parliament of the World’s Religions. He was deeply involved in the development of the United States Holocaust Memorial Museum in Washington having served four terms on its board by presidential appointment.

On the social ethics front John has worked with the Office of Justice & Peace at the National Conference of Catholic Bishops on its Energy Statement and its Pastoral Letter of the Economy. He has been a participant in three United Nations international conferences on world peace, on alternative energy and on human trafficking. He was a member of the U.S. governmental team that negotiated the termination of the United Nations Trusteeship for Micronesia.

In 2014 the Catholic Theological Society of America conferred on John its annual John Courtney Murray Award. He was awarded fellowships by Cambridge University (UK), The Catholic University of Leuven (Belgium) and the Graduate Theological Union (Berkeley, CA) and awarded Honorary Doctorates by Hebrew Union College, Dominican University and the Catholic University of Australia.