This dissertation is a social history of Jewish religious experience in Central Europe during the nineteenth century, primarily told through the life and work of one of its founding rabbis, Adolf Jellinek (1821-1893). In response to Enlightenment ideology, emancipation, and urbanization, from about 1830 to 1860 three major changes occurred in institutional Jewish religious life, changes that transformed the very essence of what the practice of Jewish religion meant between the pre-modern and modern periods. First, the role of the rabbi in the life of the Jewish community shifted fundamentally. Second, because of demographic shifts brought about by emancipation and economic conditions, the monumental urban synagogue became the dominant space for the expression of Jewish religious activity and expression in European cities. Third, the sermon became an integral part of Jewish religious practice and rabbinical responsibility, one that introduced a new form of public Jewish theology focused on individual belief and history (the constituent components of “religion” as it came to be defined in modern Europe). The Moravian-born Austrian rabbi Adolf Jellinek was both creator and observer of these myriad changes. He was the recipient of a world that (within a relatively short time) lacked many of the legal and cultural discriminations that had kept his parents and grandparents from a more robust participation in European cultural and civic life. His innovative uses of Jewish texts within the new practice of the public weekly sermon, coupled with his prominence as the head of the Viennese community, make him one of the founders of modern Jewish religious practice as we understand it today. This dissertation places Jellinek’s life and writings within a broad framework of religious institutional and practical reinvention in the middle decades of the nineteenth century. It draws our attention toward an overlooked figure, and points toward many avenues of further research concerning the impacts of urbanization and Enlightenment ideology on Jewish rabbinical and synagogue reformation in the nineteenth century.