He joined the Irgun while in high school. When he finished school, he served for a year in the Palmach (the elite Haganah unit) as a condition for continuing his studies at the Hebrew University (a Jewish Agency ruling obliged every high-school graduate to spend a year working on a kibbutz or serving in the Palmach). When he returned to Jerusalem, he enrolled at Hebrew University, faculty of humanities, and resumed his activity in the Irgun, this time in the Fighting Force.
He took part in numerous military operations, one of them was blowing up of Goldschmidt House Officers Club.
In the raid on Acre jail, on May 4, 1947, he commanded the covering force (together with Yaakov Weiss and Meir Nakar), which continued to fight until captured by the British. The three Irgun fighters were tried in a military court and were sentenced to death. On July 29, 1947 Avshalom Haviv was hanged at the Acre jail, together with his tow comrades: Meir Nakar and Yaakov Weiss. Haviv was 21 when he went to the gallows.