Born in Jerusalem in 1923 as Shmuel Katsnelson and after the State of Israel was established changed his name to Tamir (his underground cover name).

Joined the Irgun in 1938 and after the declaration of the Revolt (February 1944) took part in operations against British targets.

Was in charge of the attack on the Income-Tax offices in Jerusalem (February 26, 1944).

During 1946 served as Deputy Commander of the Jerusalem District and was in charge of the Irgun Intelligence unit in Jerusalem.

Was arrested by the British several times for short periods. In March 1947 was arrested again and exiled to Kenya Detention Camp where he finished his Law studies. In the camp he served as the Supervisor who represented the detainees to the British Authorities.

Returned home with the last exiles from Kenya on July 12, 1948, after the State of Israel was established.

Was later known as a brilliant lawyer who conducted several famous political cases; among them the Yedidya Segal Case, the Kastner Trail and many more.

Was active in the Herut Party and later in "Hamerkas Hahofshi" and Da"sh parties. Was a member of Kneset (the Israeli Parliament) from the sixth to the ninth. Served as an outstanding Minister of Justice in Begin's government (1977-1980).