As a child, she never knew her biological parents; during her infancy, she was left outside the doors of a church with a note pinned to her saying that her name was Olivia Rockefeller.

[3] In 1937, she was signed under contract to Warner Bros. Studios and made her film debut in The Prince and the Pauper which was released that year.

Her other screen credits include parts in such films as Jezebel (1938), Cowboy from Brooklyn (1938), The Amazing Dr. Clitterhouse (1938), Eternally Yours (1939), When Tomorrow Comes (1939), Broadway Melody of 1940, Ball of Fire (1941), How Green Was My Valley (1941), Shadows on the Stairs (1941), Mrs. Miniver (1942), Ministry of Fear (1944), Song of the South (1946), Out of the Past (1947), Miracle on 34th Street (1947), and Life With Father (1947).

In 1963, her last acting role was as a Roman Catholic nun in the television series, Going My Way, starring Gene Kelly and modeled after the 1944 Bing Crosby film of the same name.

[2] On June 12, 1996, two days after her 87th birthday, Mary Field died at her home in Fairfax, Virginia, of complications from a stroke.