Mundy was born on January 4, 1915 in London, England as Margaret Ane Mary Mundy.
Her roles on daytime soap operas included Eugenia Von Voynavitch on All My Children, Isabelle Alden in Loving, Mona Croft on The Doctors, and Julia Stoddard in The Guiding Light.
Mundy received a Daytime Emmy Award nomination in 1982 in the Outstanding Supporting Actress category for her work on The Doctors.
Her film credits included Ordinary People, Someone to Watch Over Me, Fatal Attraction, Oliver's Story and Eyes of Laura Mars. She also played roles in a number of primetime television series, such as Law & Order, Naked City, Alfred Hitchcock Presents and Tales of Tomorrow.
Mundy is survived by her son Sotos and granddaughter Margaret Yannopoulos.