Born in 1887 in Belorussia, Katznelson becomes involved in Zionist Socialism at a young age, taking a job teaching Hebrew literature and Jewish history at a school for poor girls in his town of Bobiruisk. Making aliyah in 1909, he becomes disillusioned with the poverty of Jewish workers in Palestine and creates a group of small landholders working in a cooperative fashion, building the foundation for the modern Moshav movement. He likewise advocates for a labor-based society in Israel, developing a philosophy that eventually forms the basis of the Mapai party (Israel’s dominant political party until the late 1970s).