Susanne Witte worked for the city of Berlin as a youth social worker. During her training she met Ruth Casper, who came from a Jewish family and had converted to Catholicism. Ruth lived with her mother, the chamber singer Regina Kirschbaum. In June 1942 Ruth Casper was deported. Before that, Witte promised her friend she would look after her mother if necessary.
Susanne Witte lived near the Putlitzstraße freight station in Moabit. She watched Jews being taken from an assembly camp to the station more and more often. When she learned that Regina Kirschbaum had been forced to live in an apartment for Jews, Witte visited her there and helped her with essentials. In September 1942 Regina Kirschbaum managed to hide in the basement during a raid. She turned to Susanne Witte for help. Witte hid Kirschbaum in her home until the end of the war, with brief interruptions. She was supported by members of her Catholic church community in Moabit.
Susanne Witte was awarded the federal cross of merit for her help in 1982. Yad Vashem honored her as Righteous Among the Nations in 1998.