He did his doctorate at the Pontifical Gregorian University in Rome, where he also taught for three years, prior to coming to the Graduate Theological Union and the Jesuit School of Theology-at-Berkeley in 1993, where he taught for a decade before joining the faculty of the University of San Francisco. He has also taught for several years in Korea at Sogang University and is a regular Visiting Professor of Moral Theology at the Loyola School of Theology of the Ateneo de Manila, Philippines where he teaches Moral Theology and Bioethics. Besides teaching Fr. Bretzke worked for 13 years on weekends at Our Lady of Lourdes Parish in Oakland, and was very active in giving workshops in various aspects of moral theology throughout the dioceses of California and Nevada