At 21, Joachim Prinz received his Ph.D. in Philosophy, and had minored in Art History, at the University of Giessen. He was ordained as a rabbi at the Jewish Theological Seminary in Breslau. He married Lucie Horovitz, the daughter of the seminary's most prominent professor. She died in Berlin in 1931, shortly after giving birth to their daughter Lucie. Prinz married Hilde Goldschmidt in 1932. They had four children, Michael (born in Berlin), Jonathan, and Deborah (both born in the United States), and they adopted another daughter, Jo Seelmann, who was Hilde’s cousin and who had survived a Nazi concentration camp.