Hillel joined the Irgun a year later, and took part in reprisals against Arab rioters. In 1938, he was arrested for two months after taking part in a demonstration against the hanging of Shlomo Ben Yosef. In 1941, he was arrested again, and detained at Atlit, Mizra and Latrun for two years.
After being released, Hillel took part in the first operations of the Revolt: the blowing up the income tax offices in Haifa, and also commanded the attack on the District British Intelligence offices in Haifa.
Hillel's positions included: commander of Southern District and then commander of Haifa and the North.
On April 1, 1944, he was arrested again and jailed at Acre. Hillel was exiled to Africa with the first transport of 251 prisoners (October 19, 1944). He succeeded in escaping with several comrades from the Kenya detention camp on March 29, 1948, and a week later reached Paris by plane.
In France, Hillel helped organize the embarkation of the Altalena.
Sources: The Irgun Site