Yehuda, son of Malka and Ephraim Yitzhak, was born in Lodz on 1925 to a family of ten children, with Yehuda being the baby of the family. The family was religious, and the father was both the beadle of the synagogue and the owner of a butcher shop. The mother worked in the business, while the father was involved in charity and helping those in need surreptitiously. Their financial situation was comfortable.
In 1936, after receiving certificates, they made aliyah and settled in Tel Aviv, where the father opened a butcher shop, and Yehuda studied in cheder with the father of Rabbi Yedidya Frankel. He then continued at the Sinai School. His parents developed a deep friendship with Rabbi Frankel, and the father became the beadle of their synagogue.
After elementary school, Yehuda started working, and at age fourteen, in 1939, he joined the IZL. Half a year after the split, he joined Lehi, and he started training with firearms and trailing British officers, as well as putting up posters in public places. He started working at the shop where they printed the posters. The arrest of many of his acquaintances in the movement compelled him to move to Netanya. He changed his named to Admoni and decided to operated independently in Netanya, without contacting the local members of the movement. He put up posters which he brought from Tel Aviv.
His occupation during this time was diamond-polishing. Even though he knew that some of his co-workers were Lehi men, he did not contact them. His only ally was Yarkoni, with whom he laid mines in the Sharon area.
In 1945, he married Shoshana Golob, who was also a Lehi member. After Anshel Shpilman was arrested, his contact was Mazal, who taught him how to write in code, for underground activity.
In 1947, the family moved to Nahalat Yitzhak, near Tel Aviv, as the Hagana was on to him. Once he was in the Tel Aviv area, he started working with Dept. 6 (Intelligence). He would follow British police and also purchase firearms. Once the State was established, he followed his Lehi comrades to Battalion 82 of the 8th Brigade. He fought in every battle in the Negev, except at Beersheba, as he was wounded and in hospital.
He served in the reserves as well, travelling to France train as a tank commander. He worked as a driver for Mekorot for a while, but then he returned to the profession of diamond polishing.
In 1969, Shoshana, Yehuda and their son moved to the United States.
They had three more children, a daughter and two sons. The daughter is a war widow, as her husband was killed in action in the Yom Kippur War. She was left with a small child and pregnant. One son ended up staying in the United States.
In 1994, the family returned and settled in Tel Aviv. For health reasons, they moved to Eilat in 1998.
Shoshana suddenly passed away on 5.5.2000, and she was buried in the Lehi section in Tel Aviv. Yehuda occupied himself with business, politics and public causes for the next dozen years, until he passed away in 2012.