Arrested for her efforts to fight fascism, she was deported with her mother and childhood friend by Nazi officials to the Ravensbrück concentration camp in Germany; she then went on to survive both her imprisonment there and a death march.

By 1944, she was involved with a cell which was partnering with Soviet paratroopers who had been sent from Moscow to help expand local anti-Nazi efforts, including hiding and transporting other members of the resistance.

[3] According to historian Elissa Mailänder, when Zimmermann was interviewed later about her experiences, she recalled that "the female guards at Ravensbrück ... used violence as a means of impressing their male colleagues.

[5] In addition, she co-founded the Österreichische Lagergemeinschaft Ravensbrück & FreundInnen (Austrian Camp Community Ravensbrück & Friends), and spoke regularly to school and community groups about her war-time experiences in order to help youth and adults better understand the economic and social climate which developed in Austria during the 1930s and 1940s.

[6] In 1999, Hilde Zimmermann participated in a lengthy series of interviews with Brigitte Halbmayr for the Ravensbrück Video Archive of the Institute for Conflict Research.