Aron was born to a middle-class Jewish family in Slonim, a part of Poland between the two world wars. His parents owned a clothing store. After studying in a technical school, Aron worked as a motion-picture projectionist in a small town near Slonim. The Soviet army took over Slonim in September 1939. War broke out between Germany and the Soviet Union in June 1941. Aron returned to Slonim. The Germans soon occupied Slonim, and later forced the Jews into a ghetto.