During the 1936 riots, was one of the activists who demanded reprisals against the Arab rioters. Among other tasks, served as newscaster on the Irgun radio station, and wrote the propaganda material.
After the arrest of David Raziel (May 19, 1939), he became Commander in Chief of the Irgun. During his term of office, the Irgun began to conduct operations against the British. After the split in the Irgun, he joined the camp of Avraham Stern ("Yair") but left shortly afterwards due to ideological differences.
On February 4, 1942, after his picture was published in the press by the British authorities and a reward of 1000 pounds was offered for information leading to his arrest, he gave himself up to the police. He was exiled to Africa in the first transport of 251 detainees (October 19, 1944).
Returned to Israel with the last exiles from Kenya on July 12, 1948.
Was a member of the Hebrew Language Academy and in charge of language standards at the Broadcasting Authority. Worked as an editor for the Bialik Institute.