Marthe Keller was born on January 28, 1945, in Basel, Switzerland, where she was raised. As a child, she was enrolled in ballet classes, but her career in dance was tragically cut short due to a skiing accident at the age of 16.
Keller redirected her passion towards acting, and her early credits include uncredited roles in Funeral in Berlin (1966) and Wilder Reiter GmbH (1967). Her breakthrough came with a series of French films in the 1970s, including Un cave (1972),La raison du plus fou (1973),and And Now My Love (1974).
Her most notable American film appearances include her Golden Globe-nominated performance alongside Dustin Hoffman in Marathon Man (1976) and her portrayal of an Arab terrorist who leads an attack on the Super Bowl in Black Sunday (1977). Keller also starred alongside William Holden in Billy Wilder's romance drama Fedora (1978) and collaborated with Al Pacino in the auto racing film Bobby Deerfield (1977).
Later films include Dark Eyes (1987),where she co-starred with Marcello Mastroianni. Keller's extensive career has also seen her take on various stage roles, including Mrs. Bertholt in the Broadway adaptation of Abby Mann's play "Judgment at Nuremberg" in 2001, for which she received a Tony Award nomination for Best Featured Actress.
In addition to her work in film and theatre, Keller has developed a remarkable career in classical music as a speaker and opera director. She has performed the speaking role of Joan of Arc in the oratorio "Jeanne d'Arc au Bûcher of Arthur Honegger" on several occasions, working with esteemed conductors such as Seiji Ozawa and Kurt Masur. She has also recorded the role for Deutsche Grammophon with Ozawa (DG 429 412-2).
Keller has also recited the spoken role in Igor Stravinsky's "Perséphone" and has performed classical music melodramas for speaker and piano in recital. The Swiss composer Michael Jarrell wrote the melodrama "Cassandre", after the novel of Christa Wolf, specifically for Keller, who gave the world premiere in 1994.
Her directorial debut was "Dialogues des Carmélites" for Opéra National du Rhin in 1999, which received a semi-staged performance in London that year. She has also directed "Lucia di Lammermoor" for the Washington National Opera and the Los Angeles Opera, as well as her directorial debut at the Metropolitan Opera, a 2004 production of "Don Giovanni".
Keller is a mother to one son, Alexandre de Broca, from her relationship with director Philippe de Broca.
