Marmont was born in August 1921 in
Beechhurst, Queens, New York, the daughter of film actor
Percy Marmont. During World War II, she served in the
Women's Army Corps (WAC) and was stationed in England. In 1949, she appeared opposite
Cary Grant in
I Was a Male War Bride, in which she portrayed a lieutenant from
Boston, Massachusetts based in England during wartime. For a period, she was married to character actor
Nigel Green. The two later divorced, and Green died from an accidental overdose of sleeping tablets in 1972. She retired from acting in the 1970s and relocated to London. During this period, Marmont become a theatrical agent, working first with
Larry Dalzell (1933–2011) for many years. In 1983 she formed her own company, Marmont Management Ltd, and became hugely successful, representing the likes of actors
William H. Macy,
Guy Henry,
Patricia Routledge,
Kenneth Branagh,
Alex Jennings, and
Julia Ormond. ==Personal life and death==