 His father-in-law died in December 1888, and Breuer succeeded him as the rabbi of the Frankfurt "Austrittsgemeinde" (secessioned community) in 1890.In Frankfurt he participated in the Freie Vereinigung, a national organisation of Orthodox communities, and created its rabbinical representative body, the "Verband der orthodoxen Rabbiner Deutschlands" (Union of Orthodox rabbis in Germany).He would later also be one of the founding members of Agudas Yisroel, and was a strong opponent of political Zionism; he viewed participation in the Zionist movement as an implicit approval of the idea that a Jewish state can replace Jewish religious identity.