Wiebke Mollenhauer grew up in Ilmenau. After completing her acting training at the Theaterakademie Hamburg, she spent six months assisting a doctor in India and then joined the Schauspiel Frankfurt from 2011 to 2014. She appeared as a guest performer at the Burgtheater in Vienna as Ophelia in Andrea Breth's production of Hamlet. Since 2017, she has been appearing as Anna in Trommeln in der Nacht (Drums in the Night), directed by Christopher Rüping, at the Munich Kammerspiele (invited to the 2018 Berlin Theatertreffen)

From 2014/15 to the 2018/19 season, Wiebke Mollenhauer was a member of the ensemble at the Deutsches Theater Berlin. For the 2019/20 season, she was a member of the ensemble at the Schauspielhaus Zürich. Since the 2024/25 season, she has been a member of the ensemble at the Deutsches Theater.