Ira Eisenstein (November 26, 1906 – June 28, 2001) was an American rabbi who, along with his mentor and—through his marriage to Judith Kaplan—father-in-law, Rabbi Mordecai Kaplan, founded Reconstructionist Judaism over a period spanning the late 1920s through the 1940s.
[1] A native of Manhattan, New York, Rabbi Eisenstein obtained his bachelor's and doctoral degrees from Columbia University.
In 1931, he was ordained by the Jewish Theological Seminary (JTS); during his studies, he met and married Judith Kaplan, the daughter of JTS faculty member Rabbi Mordecai Kaplan.
He also served as the religious leader of the Anshe Emet Synagogue in Chicago and the Reconstructionist Synagogue of the North Shore on Long Island, N.Y.[2] A former president of Conservative Judaism's Rabbinical Assembly of America, Rabbi Eisenstein served as president of the Jewish Reconstructionist Federation from 1959 to 1970.
Alongside Rabbis Jack Cohen, Milton Steinberg, and Eugene Kohn, Eisenstein was one of Kaplan's main disciples.