At the age of 17 he enlisted in the British army, after forging his birth certificate.
On demobilization, in 1946, he became a member of the Irgun. At first he was active in recruitment and propaganda work, and then moved to the Fighting Force. He took part in several operations, sometimes with Avshalom Haviv, his commander in their final operation, the Acre prison-break (may 4, 1947). He was captured (together with two of his comrades: Avshalom Haviv and Yaakov Weiss) by the British. The three Irgun fighters were tried and sentenced to death. On July 29, 1947 Meir Nakar was heanged at the Acre jail, together with Haviv and Weis. He was 21 when he went to the gallows.