London-born of Irish parents, Geraldine Brianne Murphy was educated in English and American schools before she set her sights on an acting career and attended the Neighborhood Playhouse in New York City.

In order to become "more American," she worked as a trick rider with a rodeo for a season, and later "crashed" the Ringling Brothers and Barnum & Bailey Circus at Madison Square Garden on opening night, in 1954, performing the entire evening as a clown. The resulting publicity helped her land a job as a still photographer with the traveling circus and eventually led to her arrival in Hollywood, where she began working with low-budget filmmakers Jerry Warren and Ralph Brooke (both of whom she married).

She was the first-ever woman director of photography on a major studio, union picture (Fatso (1980)) and has had several Emmy nominations (and one win) for cinematography. She also won a 1982 "Scientific and Engineering" Academy Award.