Belarus-born Katznelson co-founded the Histadrut labor federation and advocated for labor unity to uplift Jewish workers and small landholders. Immigrating to the Land of Israel in 1909, Katznelson became involved in labor councils. He helped found a consumer cooperative, worker health fund Kupat Holim; a labor publishing house; and a precursor of Mapai. He was founding editor of labor newspaper Devar and served on the Jewish National Fund board.
Photo: Central Zionist Archives