scholar, educator, editor, and Conservative Jewish leader who had great influence on American Jewish life in his time.

Adler received his Ph.D. in Semitics in 1887 from Johns Hopkins University, where he later taught Semitic languages. In 1892 he founded the American Jewish Historical Society, of which he was president from 1898 until 1922. For the Jewish Publication Society of America, he planned the American Jewish Year Book, which he edited from its first year (1899) until 1905 and again in 1916. Under his chairmanship, the Bible Committee of the Jewish Publication Society published the first authoritative Jewish translation of the Hebrew Scriptures in the English language (1917).

Adler helped develop the Jewish Theological Seminary (Jewish Theological Seminary of America) in New York City, an institution for research in Judaica and the training of rabbis; he did so principally by bringing Solomon Schechter (Schechter, Solomon) from Europe, in 1902, to head the institution. In 1908 Adler became the first president of Dropsie College for Hebrew and Cognate Learning, in Philadelphia. There Adler published and edited the Jewish Quarterly Review, which had been previously printed in England. With Schechter, in 1913, he created the United Synagogue of America, a laymen's organization that remains the chief organ of Conservative Judaism in the United States. When Schechter died in 1915, Adler became acting president of the Jewish Theological Seminary and from 1924 until his death served as president. During his tenure, the seminary accumulated one of the world's foremost collections of Judaica.