Born Signe Larsson in Stockholm, Sweden, at the age of twelve Hasso became one of the youngest students to be accepted to the prestigious Royal Dramatic Theatre. She made her first film in 1933 and in 1940 moved to the United States where she was signed to a contract by RKO Studios who promoted her as "the next Garbo". Her first role of note was as the beautiful "Mademoiselle" in Heaven Can Wait (1943). Her other roles during the 1940s included The Seventh Cross (1944), Johnny Angel (1945), A Scandal in Paris (1946) and A Double Life (1947).

By the 1950s her Hollywood career had stalled, and in 1954 her son was killed in a car accident. From then she divided her time between making films in Sweden and acting on stage in New York until she returned to Hollywood in the mid 1960s.

In her later years, Hasso won acclaim for her work as a poet and writer, and for her work translating Swedish folk songs into English. She also continued acting, making her final appearance in 2001, in a television documentary about Greta Garbo.

In 1972 the King of Sweden awarded her The Royal Order of Vasa, with the rank of Knight First Class -- the equivalent of the English knighthood. She died in Los Angeles from pneumonia, which resulted from lung cancer.

Signe Hasso has a star on the Hollywood Walk of Fame for her contribution to motion pictures, at 7080 Hollywood Boulevard.