Birger Malmsten (1920–1991) was a Swedish actor, known primarily for his intense collaboration with director Ingmar Bergman, for whom he was a key performer in the early post-war period. His artistic partnership with Bergman began with *Crisis* (1946) and continued in numerous films such as *Thirst* (1949), *Music in Darkness* (1948), and *To Joy* (1950), in which he often embodied youthful, sensitive, and tormented characters. His career, spanning nearly fifty years, also included important stage roles at the Royal Dramatic Theatre in Stockholm and appearances in films by other directors and in television productions, later returning to work with Bergman on subsequent works such as *The Silence* (1963) and *Scenes from a Marriage* (1973). For his performance in the film *Falsk som vatten* (1985), he received the prestigious Swedish Guldbagge Award for Best Actor in a Leading Role, crowning a long and significant career in Scandinavian cinema and theatre.