Kretzmer was born in Johannesburg, South Africa and emigrated to Israel in 1963. He received his Bachelor of Laws from the Hebrew University of Jerusalem in 1967, and his Master of Laws in 1972. He worked as a law clerk to Justice Zvi Berinson at the Supreme Court of Israel from 1966 to 1967, and with the firm of Yigal Arnon in Jerusalem until 1968, when he was admitted to the Israeli Bar. He was teaching assistant to Aharon Barak and became part-time teacher at the Faculty of Law of the Hebrew University in 1969 and worked as an advocate with D.M. Schlosberg, Advocates in Tel-Aviv until 1972, when he entered Osgoode Hall Law School at York University in Toronto, Canada, where he obtained a Doctor of Laws in 1975 with a dissertation about Aims and functions of the tort system of loss allocation. He became lecturer in law at the Hebrew University in 1975, being appointed to the Louis Marshall Chair of Environmental Law in 1976 and to senior lecturer in 1978. From 1981 till 1984 he was vice-dean for students’ affairs at the Faculty of Law of the Hebrew University and became associate professor in 1984 and full professor in 1991, when he was appointed both professor of the Faculty of Social Sciencies' School of Public Policy and the Faculty of Law, where he held the Bruce W. Wayne Chair of International Law until 2006. He was Visiting Professor of Law at the University of Southern California, Tulane University, Bar-Ilan University, Columbia University, and Visiting Fellow at the MIT in Cambridge, Massachusetts, the Institute for Advanced Legal Studies of the University of London, and the Max Planck Institute for Comparative and Foreign Law in Heidelberg. In 2006 he joined the Transitional Justice Institute at the University of Ulster. His fields of interest are constitutional law, judicial decision-making, human rights and international humanitarian law. He has taught torts, contract, constitutional law, administrative law, international human rights and international humanitarian law. Kretzmer was a founding member of the Association for Civil Rights in Israel in 1972 and served as chairperson on its executive board. In 1993 he established the Centre for Human Rights at the Hebrew University, and from 1997 till 2000 he served as first academic director of the Minerva Centre for Human Rights, a joint centre of the Hebrew University and Tel Aviv University. He was a member of the UN Human Rights Committee under the International Covenant on Civil and Political Rights from 1995 to 2002, and vice-chairperson in 2001 and 2002. He was on the founding council of the Israeli Information Center for Human Rights in the Occupied Territories B'Tselem, and is a member of its executive board, and served on the first executive committee of HaMoked, the Center for Defence of the Individual in Israel. He was elected a commissioner of the International Commission of Jurists in 2003 and re-elected in 2008. In 2010, the Minerva Center for Human Rights established a research fellowship for research in Human Rights Law in honor of Kretzmer and his late wife Marcia.
