A rabbi is a spiritual leader or religious teacher in Judaism. One becomes a rabbi by being ordained by another rabbi—known as semikha—following a course of study of Jewish history and texts such as the Talmud. The basic form of the rabbi developed in the Pharisaic and Talmudic eras, when learned teachers assembled to codify Judaism's written and oral laws. The title "rabbi" was first used in the first century CE. In more recent centuries, the duties of a rabbi became increasingly influenced by the duties of the Protestant Christian minister, hence the title "pulpit rabbis", and in 19th-century Germany and the United States rabbinic activities including sermons, pastoral counseling, and representing the community to the outside, all increased in importance.

Reconstructionist Judaism is a Jewish movement based on the concepts developed by Rabbi Mordecai Kaplan (1881–1983) that views Judaism as a progressively evolving civilization rather than just a religion. The movement originated as a semi-organized stream within Conservative Judaism, developed between the late 1920s and the 1940s before seceding in 1955, and established a rabbinical college in 1967. Reconstructionist Judaism is recognized by many scholars as one of the five major streams of Judaism in America alongside Orthodox, Conservative, Reform, and Humanistic.