Immigrated to Eretz Israel in 1932 and a year later joined the Irgun. Accompanied David Raziel on the operation in Iraq.
After Raziel's death, was appointed Irgun Chief Commander.
In 1943, Meridor relinquished command of the Irgun to Menahem Begin. Held senior positions in the Irgun until the Haganah handed him over to the British (1945). Was in various detention camps in Africa with other members of the underground, and carried out daring escape attempts. In 1948 an escape succeeded and he arrived in Israel on the day the state was declared. Begin assigned him the task of dealing with the Irgun's integration in the IDF.
One of the founders of Herut movement and served as member of the First to the Sixth Knesset. In 1981 was appointed by Prime Minister Begin as Minister of Economics and Planning .
Published a book "Long is the Way to Freedom".