Thaxter was born in Portland, Maine, one of three children of Phyllis (néeSchuyler) Thaxter, a former actress, and Sidney St. Felix Thaxter, who later served as a Justice of the Maine Supreme Court.[2]
Phyllis Thaxter's siblings were Sidney Thaxter and Hildegarde Schuyler Thaxter Niss Gignoux.[citation needed]
Before appearing in films, Thaxter was on the stage. When Dorothy McGuire went to Hollywood, Thaxter replaced her in the Broadway play Claudia.[3] In 1944, she signed a contract with Metro-Goldwyn-Mayer. Her movie debut was opposite Van Johnson in the 1944 wartime film Thirty Seconds Over Tokyo.[2] In the 1945 film-noir Bewitched, Thaxter played Joan Alris Ellis, a woman with split personality. In 1948, she played a cattle owner's daughter in Blood on the Moon.
Patricia Bosworth, in her biography of Montgomery Clift, tells of Thaxter's close relationship with Clift in the early 1940s, writing that they "seemed so close that a great many people assumed they would eventually marry".[3]
While at MGM, Thaxter married James T. Aubrey Jr., who later became president of CBS-TV and MGM. They divorced in 1962. They had two children: Susan Schuyler "Skye" Aubrey, an actress, and James Watson Aubrey. In 1962, Thaxter married Gilbert Lea. They were married for 46 years until his death on May 4, 2008.[6]