He joined the Irgun and fulfilled various senior functions: served as Commander of the Dan-Sharon District. In 1945, he was made a member of the General Headquarters headed by Menahem Begin and was in charge of organization.
After the arrest of Yitzhak Avinoam, he served for a short period as Commander of Jerusalem District.
Was involved in organization of numerous operation and in one of them, the assault on Lydda airfield, he took part as a rank-and-file fighter.
After Israel was established, he changed his name to Amitzur (which had been his cover name in the underground). He was chairman of the board of directors of Maman and founded the Irgun Museum at Jabotinsky House.