Yitzhak Shamir (Jeziernicky) was born in Rozhinoy, Belarus, October 15, 1915. He studied at a Hebrew High School in Białystok, Poland. As a youth he joined Beitar, the Revisionist Zionist youth movement. He studied at the law faculty of Warsaw University, but left to make aliyah in 1935. In 1944 he married Shulamit Shamir (1923–2011). They had two children, Yair and Gilada.
Shamir joined the Irgun, a Zionist militant group that opposed British control of Eretz Israel. When the Irgun split in 1940, Shamir joined the more militant Lechi faction, known as the Stern Gang.
In 1941 Shamir was imprisoned by the British. After Avraham Stern was killed by the British in 1942, Shamir escaped from a detention camp and became one of the three leaders of the group in 1943. In 1944, he was exiled and interned in Africa by British Mandatory authorities. He was freed, along with the other detainees, after the Israeli Declaration of Independence in 1948.
In 1955, Shamir joined the Mossad, serving until 1965. He directed the assassinations of former Nazi rocket scientists working on the Egyptian missile program.
In 1969, Shamir joined the Herut party headed by Menachem Begin and was elected to the Knesset in 1973 as a member of the Likud. He became Speaker of the Knesset in 1977, and foreign minister in 1980, before succeeding Begin as prime minister in 1983.
Shamir served several terms as prime minister throughout the 1980s. He maintained a hard political line, which strained his relations with the U.S. Shamir opposed the Madrid peace talks, and then President George H.W. Bush retaliated by holding back approval for loan guarantees to help absorb immigrants to Israel from the former Soviet Union. Shamir gave in and in October 1991 participated in the Madrid talks. After the talks, his government collapsed and in 1992 he was defeated by Yitzhak Rabin.