Benary-Isbert was born in Saarbrücken, in the Rhine Province of the Kingdom of Prussia, and raised in Frankfurt am Main, part of the German Empire but outside the Kingdom. She enjoyed telling stories and a schoolteacher recommended writing them up as fiction rather than sounding like lies; her first story was published when she was 19. She attended the College St. Carolus and the University of Frankfurt briefly and worked as a secretary at the Museum of Ethnology and Anthropology in Frankfurt from 1910 to 1917. In 1917 she married Wilhelm Benary, a psychologist. They moved to a farm house in Erfurt where William ran the family business. Margot raised Great Danes for a time.
