Fanny Löwenthal was the second of three daughters of the Bad Kissingen livestock dealer and producer of mattresses Maier Löwenthal and his wife Clothilde, née Ehrmann from Darmstadt. She was born in Bad Kissingen on May 6, 1906. The family lived in Promenadestrasse 3.

Nothing is known about her childhood and youth. In August 1938, Fanny Löwenthal left Bad Kissingen with her parents in order to emigrate to America. Before setting out, they visited the oldest daughter Irene, m. Appel, who had already emigrated to the Netherlands in 1933. Those were to be the last days together with her. After the occupation of the Netherlands by German troops, Irene Appel was deported from Westerbork to Auschwitz/ Oświęcim Concentration Camp (1943) and murdered there. On August 30, 1938 Fanny Löwenthal and her parents embarked for New York in Le Havre on board the “Ile de France”. Her sister Bertha had emigrated to the USA one year earlier. In 1940, they all lived together in an apartment in New York.

After her father’s death in 1951, Fanny Löwenthal stayed on living with her mother and cared for her. She remained unmarried all her life and died in New York in April 1988 at the age of 81.