Pernilla August started acting as a child, performing in plays at Vår teater and at school. In 1979 she was accepted at the Statens scenskola to study acting professionally. Director Ingmar Bergman took note of her early and cast her as a nanny in his Fanny och Alexander (1982).

In 1982 she got married to author Klas Östergren and started work at the Folkteatern in Gävle, appearing in August Strindberg's A Dreamplay and Anton Chekhov's Three Sisters. She returned a few years later to the Royal Dramatic Theatre in Stockholm for roles in William Shakespeare's Hamlet and Henrik Ibsen's A Doll's House (as Nora).

Until then she hadn't had any bigger experience of television or movies but Ingmar Bergman specifically asked for her to play his mother in the biographical Den goda viljan (1992) By then her marriage was over and she started a relationship with director Bille August whom she married in 1991 - and had her name changed for the second time. He offered her a role in his The House of the Spirits (1993), but due to her pregnancy the role went to Winona Ryder instead.

She has admirably managed an international career despite having three daughters. She is best known for her appearances in films like Star Wars: Episode I - The Phantom Menace (1999) or I Am Dina (2002).