Dawn Addams was born in Felixstowe, East Suffolk, England, to Captain James Ramage Addams, a Royal Air Force officer. Her childhood was spent in Calcutta, India, where her father was stationed, and later in England and California, where she attended schools.
Despite taking her first screen test at the age of thirteen, Dawn did not start her acting career until after graduating from the Royal Academy of Dramatic Art in London. She began her career on the repertory stage, touring both Britain and continental Europe.
In 1950, Dawn was signed to a contract by Metro-Goldwyn-Mayer and made her feature film debut in Night Into Morning (1951). She went on to appear in several well-received A-grade productions, including Plymouth Adventure (1952),Young Bess (1953),and The Robe (1953).
In 1953, Dawn joined other MGM contract stars on a USO tour of Korea and appeared in Otto Preminger's The Moon Is Blue, which was rented out by MGM to United Artists. That same year, she also starred in Charles Chaplin's A King in New York as an advertising woman who gets involved with royalty.
In her personal life, Dawn married Italian nobleman Don Vittorio Massimo in 1954, becoming an actress-princess before Grace Kelly. The marriage ended in separation after four years and was dissolved in 1971.
By the early 1960s, offers of glamorous roles had diminished, and Dawn was relegated to playing hapless heroines in European co-productions, second-string horrors like The Two Faces of Dr. Jekyll (1960),and potboilers like Fritz Lang's The 1,000 Eyes of Dr. Mabuse (1960).
Dawn spent the remainder of her career alternating between stage and television work in England, eventually remarrying and settling down in Malta. In April 1985, she was treated for cancer in Florida but died soon after at a London hospital at the age of 54.