Shmuel Binyamin was born on 27 April 1929, in Jerusalem, in the Yemin Moshe neighborhood. His father, Nissan Kirschenbaum, of Safed, worked for the Egyptian Mantacheff Oil Company, and he was the first oil agent in the Land of Israel. His mother, Miriam née Lehrman, of Yemin Moshe, was a homemaker raising six children. His brother, Avraham Michael Kirschenbaum, was killed in the War of Independence defending their neighborhood.
Shmuel Binyamin grew up in a religious home and studied at the Etz Hayim yeshiva. At a young age, he went out to help support the family. He joined Lehi while still young and took part in a number of operations, including the attack on British officers, at Café Ritz. When the War of Independence broke out, he was one of the fighters to attack Taunus House in Mamilla, in February 1948. He also took part in the capture of Der Yassin on 9 April 1948.
After the State was established, he had trouble getting a government job, as he was considered a “dissident.” His father appealed to the attorney Shmuel Tamir, and due to the latter’s intervention, he was able to get a job at the Ministry of Heath, where he worked for the rest of his life.
In 1952, he married Rachel Elias, a seniors’ health aide, a former Lehi member in her own right. They had met during Lehi operations. They lived in Jerusalem and had a son (named Avraham Michael after his fallen uncle) and a daughter (Orit).
Shmuel Binyamin passed away of a heart attack on 21 November 1978, when he was only 49.