Aryeh Lashner was born on April 8, 1915 in New York City, to Pesach and Channa. He graduated CCNY where he majored in the social sciences with particular emphasis on education and teaching. He had received Zionist orientation under the auspices of Poale Zion both in afternoon school and in summer camp. Ari joined Poale Zion in 1932 as a young adult and quickly became an organizer and the central figure in the youth group 'Habonim'. From 1936 he was active in its summer camps all over the country. He went to Hachshara in Cream Ridge, NJ but was persuaded to return to organizational work, as a truly indispensable individual.
Ari was drafted into the American Navy in 1942, where he served as a wireless officer. Discharged in 1945, he returned briefly to general organizational work until January 1946. From then on, he focused on recruiting people to man the ships and participate generally in the 'illegal' movement of refugees from Europe to Palestine. He was himself among the first volunteers. In August 1946, Ari reached Israel on the refugee ship 'Haganah' and became a member of the Habonim Kibbutz Kfar Blum, where his wife was already residing.
In the kibbutz Ari came to specialize in electrical work. He was killed by a sniper from the east bank of Jordan on March 15, 1948 when he climbed a pole to do some electrical work. He was buried in the cemetery at Kfar Blum. He left his wife and daughter.