She appeared with husband Herbert Marshall in John Van Druten's 1931 play There's Always Juliet on both Broadway and London.

[citation needed] For Gainsborough Pictures, she starred in the melodramas Michael and Mary and The Faithful Heart alongside her husband.

Her other film credits include Intermezzo: A Love Story (1939), Swiss Family Robinson (1940), The Late George Apley and The Ghost and Mrs. Muir (both 1947), and The Iron Curtain (1948).

Best received a nomination for an Emmy Award in 1957 for her role in the Ford Star Jubilee adaptation of This Happy Breed.

[citation needed] She had appeared on television as early as 1938 in a live production of Love from a Stranger, adapted from the Agatha Christie short story "Philomel Cottage" by Frank Vosper.