She was born as Gladys Clare Evans on September 13, 1904 in Patten, Maine (Another source says Hatton, Maine; a third source says "Gladys was born in a little town in Missouri, where the troupe her parents belonged to happened to be stranded at the time.") to English parents. Her Father was Sir Arthur Claire, "noted Shakespearean actor."
George went on the stage at the age of 3 and toured the United States, appearing with her parents. She starred on stage in the 1920s, although she had made several films in the early part of that decade. She starred in Personal Appearance, a comedy by Lawrence Riley. This role was reprised by Mae West in the classic film, Go West, Young Man, which West adapted from the play. In 1936 George was nominated for an Academy Award for Best Actress for Valiant Is the Word for Carrie.
Her only other first billed roles were in Madame X (1937) and Love is a Headache. She also appeared in The Roaring Twenties (1939), The Way of All Flesh (1940), The Best Years of Our Lives (1946) and He Ran All the Way (1951). She played the widow of Miles Archer (Iva Archer) in The Maltese Falcon and Mme. Du Barry in Marie Antoinette.
George was afflicted with numerous ailments, including throat cancer, heart disease, and cirrhosis of the liver. She died from a cerebral hemorrhage in 1954 in Los Angeles, California, aged 50, and was interred in the Valhalla Memorial Park Cemetery.