- Teaching Fellow, University of Pennsylvania (1975-1979). Teaching of biblical and modern Hebrew language courses.
- Instructor, University of Pennsylvania (Summer Sessions, 1978). Teaching of modern Hebrew language courses.
- Acting Instructor, Department of Religious Studies, Yale University (July, 1979). History of early Judaism.
- Assistant Professor, Department of Religious Studies, Yale University (July, 1980). History of early Judaism.
- Associate Professor, Department of Religious Studies, Yale University (July, 1984). History of early Judaism.
- Senior Fellow, W. F. Albright Institute of Archaeological Research, Jerusalem (Summer,1984).
- Mark Taper Associate Professor of the History of Judaism, Yale University (April, 1986).
- Fellow, The Israel Institute for Advanced Studies, The Hebrew University of Jerusalem (Fall 1988; Summer, 1989). Research group on biblical interpretation.
- Mark Taper Professor of the History of Judaism, Yale University (July, 1989-).
- Halls-Bascom Visiting Scholar, Department of Hebrew and Semitic Studies, University of Wisconsin, Madison (Fall 2001).
- Sackler Scholar, The Mortimer and Raymond Sackler Institute of Advanced Studies, Tel Aviv University, Israel (Spring 2015).
- Visiting Scholar, The Israel Institute for Advanced Studies, The Hebrew University of Jerusalem (Spring 1993; Spring 2015). Research groups on ancient Jewish history and legal interpretation.
- Visiting Scholar, The Law Faculty, Hebrew University of Jerusalem (December 2017). “Legal Innovation in Jewish Law: From the Bible to the Sages.”
- Mark Taper Professor Emeritus of Religious Studies and the History of Judaism, Yale University (July 2022-).
- Visiting Instructor (Graduate Seminar), Department of Jewish Philosophy and Talmud, Tel Aviv University (Spring 2023).