Discovered at age 20 by celebrated director Ingmar Bergman, she became part of Bergman's regular stable of performers; in fact, he wrote Sommaren med Monika (1953) especially for her breakthrough. Extraordinary and versatile as an actress, her roles have ranged from the naive young wife in Gycklarnas afton (1953) to the mad visionary in Through a glass darkly (1962). Andersson also appeared in Fanny och Alexander (1982), Bergman's last film. After that she has appeared in a number of feature films and TV series in Sweden. Her autobiography was published in 2005.