Jack Klein, son of Sarah and Max, was born on June 2, 1916 in New York City. He had a Hebrew School education which included Zionist orientation. He became active in the Hashomer Hatzair youth organization, occupying a key position so that it was organizationally important for him to remain while others proceeded to Palestine.
With the start of WWII, Jack entered the U.S. Army, where he became a corporal and an expert mechanic. After the war, he succeeded in moving his mother, wife and son to Palestine although he himself could not enter because he didn't have an entry permit. Finally he succeeded in 1947 via a refugee ship. He became a member of the Hashomer Hatzair kibbutz, 'Hatsor' in the south. A major defensive tactic in the face of the expected Egyptian invasion was the laying of mine fields. This became a specialty for Jack. He was killed on May 30, 1948 in the course of setting mines in the fields of Kfar Menahem, when a mine blew up in his hands. He is buried in the cemetery at Kibbutz Hatsor.