He joined the Betar movement in Jerusalem at 13 and in 1940 he joined the Irgun. There he held many positions: first, in the intelligence service and then in the Fighting Force. Yehiel saw action many times, as a rank-and-file fighter and as commanding officer: including the attack on Lydda airbase; the assault on Yibne railway station and the attack on Ramat Gan police station.
On December 29, 1946 he was captured armed, together with Alkahi and Kashani, upon returning from an operation. They were tried before a military court and sentenced to death. At the time of his arrest, Dresner was commander of the Fighting Force at Petah Tivka, and was equipped with an identity card in the name of Dov Rosenbaum. It was under this name that he went to the gallows, on April 16, 1947 (together with Dov Gruner, Mordechai Alkehi and Eliezer Kashani) and the British and the general public remained unaware of his real identity. He was 25 when he was executed.