JUNG, LEO (1892–1987), U.S. Orthodox rabbi. Jung was born in Ungarisch-Brod (Uhersky-Brod), Moravia, son of Meir Jung who became rabbi of the London Federation of Synagogues in 1912. He pursued rabbinical studies at Hungarian yeshivot and received his rabbinical ordination first from Rabbi Mordecai Schwartz and Rabbi Avraham Kook; after World War I he returned to Berlin to receive his ordination from Rabbi David Hoffman at the Rabbinical Seminary of Berlin (1920). His secular education was at the University of London where he received his Ph.D. In 1920 he went as rabbi to Congregation Kenesseth Israel, in Cleveland, Ohio, in place of his father, who had been offered the position first.
In 1922 he became rabbi of the Jewish Center in New York, one of the most prominent Orthodox congregations in the city, where Mordecai Kaplan had been rabbi before he left Orthodoxy. He shaped the congregation into a bastion of modern Orthodoxy based on the philosophy of Torah and Derekh Eretz. Jung emerged as one of the best-known spokesmen of neo-Orthodoxy in America. He helped organize the Rabbinical Council of the Union of Orthodox Congregations, which served English-speaking rabbis, and was its president from 1928 to 1935. Together with his cross-town colleague and rival, Rabbi Joseph *Lookstein, Jung was instrumental in Americanizing the Orthodox rabbinate and in making the Orthodox synagogue prestigious for affluent Jews. He became professor of ethics at Yeshiva University in 1931 and held a similar position at Stern College for Women from 1956. During World War II he personally collected 1,200 affidavits and helped rescue some 9,000 Jews. He worked closely with Mike Tress of Ẓe'irei Agudah and with the Va'ad ha-Haẓẓalah. Active in efforts to regularize kashrut supervision in New York, Jung was appointed chairman of the New York State Advisory Board for Kashrut Law Enforcement in 1935. He was associated with the *American Jewish Joint Distribution Committee as chairman of its cultural committee (from 1940) and was a trustee of the *National Jewish Welfare Board from 1928. Jung was at one time identified with the Agudat Israel
A noted writer and editor, Jung started the Jewish Library in 1928 and edited eight volumes. His own writings numbered some 35 books. His Harvest: Sermons, Addresses, Studies appeared in 1956. Jung's 70th birthday was commemorated by the Leo Jung Jubilee Volume (edited by M.M. Kasher, 1962). His other writings included The Path of a Pioneer: the Autobiography of Leo Jung (1980) and Business Ethics in Jewish Law (1987).
Leo's brother MOSES (1891–1960) was a professor of religion. Born in Moravia, he went to the U.S. in 1922. A prolific writer, Moses Jung contributed to various Jewish publications and published several books on Jewish law, history, and education. He lectured at Columbia University from 1952. Another brother, JULIUS (1894–1975), was secretary (1925–54) and executive director (1954–59) of the Federation of Synagogues in London.