Hollywood was expanding in 1931, and movie execs were out to recruit stage actors and actresses. Helen gave in and signed a deal with Metro-Goldwyn-Mayer. Her first movie was The Sin of Madelon Claudet, the story of a poor woman forced to commit crimes to support her son. The writing was not good and audiences at the first preview hated the movie. Charlie took a stab at rewriting, which helped, but it wasn't until scenes were added and re-shot that Madelon became a classic. Helen picked up an Academy Award for Best Actress, making her the first stage actress to win an Oscar. She had established a successful career in Hollywood, and was cast opposite many of the most desirable leading men in film. Helen worked with Clark Gable and John Barrymore in The White Sister, Ramon Novarro in The Son-Daughter, and Robert Montgomery in Another Language.
The regal Broadway roles that made Helen famous started in late 1933 when she portrayed Mary Stuart in Maxwell Anderson's Mary of Scotland. That led to her role in Victoria Regina, in which she played Queen Victoria from youth to old age. This was a pinnacle of her career, for which she earned many honors and awards. She was almost unrecognizable as the old Victoria, fooling even the audience until she spoke. The reason she was so convincing was not only good makeup and props (she wore cotton pads in her cheeks to puff them out), but also because she drew inspiration from her grandmother for the queen's mannerisms. Graddy Hayes, as she was called, was an avid Victoria devotee, even dressing like her later in life.
Helen got quite a compliment once after a show. Queen Victoria of Spain, the original Victoria's granddaughter, saw Helen's performance and set up a tea time for them to meet the next day. According to Helen, Victoria said in astonishment, "How did you ever learn so many things about my grandmother? Why, you laugh like her and talk like her, and who told you of that impatient little shrug she made if anyone tried to sympathize with her or help her when she was old?" Helen replied, "I guess all old people do the same things, or, at least, Your Majesty's grandmother and my grandmother had a great deal in common."