Gal was born in Weimar, Germany to Mile and Erich Glas. When the Nazis came to power in 1933 he moved first to the United Kingdom and later, in 1936, to Kibbutz Yagur in the British Mandate of Palestine where he changed his name to Uziel Gal. In 1943, he was arrested for illegally carrying a gun and sentenced to six years in prison.