He worked as a painter, then as an iron worker in various factories in Warsaw. He joined the illegal Polish Socialist Party (PPS) in 1904, soon becoming a member of its Warsaw Committee.
During the famous demonstration on Grzybowski Square on 13 November 1904 he was the one who carried the red banner. He became a key member of the Combat Organization of the Polish Socialist Party that was responsible for protecting workers meetings and demonstrations and was organizing attacks against Russian police officers or high rank officials.