Van Acken grew up in Schleswig-Holstein, where she still lives today in a small village. As a child, she was interested in horseback riding and dancing. She first took the stage in 2011 as an extra in a production of *Der Ölprinz* at the Karl May Festival in Bad Segeberg. She did not undergo formal training as an actress; instead, she studied other actors by watching them in films.

In 2014, Van Acken played the lead role—that of the deeply religious teenager Maria—in the drama *Kreuzweg* (Stations of the Cross), directed by Dietrich Brüggemann. The film won a Silver Bear at the 2014 Berlin International Film Festival. In Brüggemann’s next film, *Heil*—a satire about neo-Nazis—Van Acken portrayed a teenager. She also played a small role in Bernadette Knoller’s RBB television film *Ferien*.

In 2015, she appeared in a supporting role in the fifth season of the US series *Homeland*, which was filmed entirely in Germany. She also appeared in the SWR television film *Sag mir nichts* and in the *Spreewaldkrimi* installment *Das Duell im Moor* (ZDF). In the film adaptation of *The Diary of Anne Frank*, Van Acken played the title role of Anne Frank. To prepare for the role of the Jewish girl who became famous through her diary, she wrote fictional letters to Anne Frank. For the final scene—which takes place in a concentration camp—the actress had her hair cut off to ensure an authentic portrayal.