Yehiel was born on October 24, 1924 in Pinsk, Belarus, to Freida and Arieh Leib, a teacher and businessman. Yehiel studied first in cheder, and afterwards in the Tarbut Gymnasium. At a young age, he joined Beitar and was educated to love the Land of Israel. He sought a way to join the nationalist cells, and in 1938, he joined the IZL. As World War II broke out in 1939, he succeeded, with some of his friends, in fleeing to Vilnius. As part of the youth aliyah program, he got a certificate and made aliyah legally. He joined Beitar in Rosh Pina, and the same year he found his way to Lehi, whose worldview he approved of. He was a manual laborer, but he continued to study and learn. Later, he Hebraicized his name.

In the underground, he took an ideological course with Dr. Eldad and started working in Department 6 (Intelligence) in the Tel Aviv region. He then was involved in recruiting members for the underground. In 1944-1947, he was active in Jerusalem in the same spheres. In a training accident among the dunes of Bat Yam, he lost a hand when a grenade detonated early. This did not break his spirit, and he continued with his underground activity. He sat on admissions boards, recruited medical assistance and found refuge for wounded fighters, and he participated in confiscating money and materials for the underground.

He was arrested twice. One time he was arrested on the street, during a routine patrol. He was held for three weeks in Jaffa, and from there he was sent to detention in Latrun, where he sat for three months. He was sent to the Abu Kabir Police Station in order to be released, but he had to bring guarantors. He managed to slip away from the British sergeant and fled. The second time, he was arrested during the three-day siege of Tel Aviv, and he was sent to detention in Rafiah. Since he carried different identification than what he was arrested with the first time, he was questioned and released. He then returned to fully active duty.

In December 1947, after the Partition Plan was announced, ideological disputes erupted between him and the central committee, due to the new circumstances and the questions about Lehi’s future. Yehiel left the underground, enlisted in the Battalion 8 of the Palmach, and served as a culture officer. Among other assignments, he taught Hebrew to the foreign volunteers who came to fight. He continued to serve in the IDF until late 1949.

In his civilian life, he worked as a social worker in Jerusalem. He married Malka Pinchas, and they had two daughters.

In his political life, he was a Maki member, and he became the Jerusalem district secretary of the party.