He was awarded a doctorate from Columbia in 1918, became a rabbi in 1919, and after many years as professor of theology at the Jewish Theological Seminary he was appointed Chancellor in 1940. He authored a number of books, including Tradition in the Making, Beliefs and Practices of Judaism, Pre-Maccabean Documents in the Passover Haggadah, Abot of Rabbi Nathan, (a three volume series on The Pharisees), and Akiba: Scholar, Saint and Martyr. He also edited a three volume series entitled The Jews: Their History (vol 1), Their Religion and Culture (vol 2), Their Role in Civilization (vol 3).