Offscreen, Bette Davis suffered a nervous breakdown during filming as a result of her crumbling marriage to Harmon Nelson. This didn't prevent her from embarking on an affair with co-star George Brent.
During the filming of the emotionally-charged scene when Bette Davis's character needs to find her way upstairs to her room after the brain tumor has caused her blindness, the cast and crew and several visitors were watching as Davis grasped the banister and began to feel her way up the steps, one by one. Halfway to the top of the staircase, Davis paused, stopped the scene, briskly walked back downstairs, and addressed director Edmund Goulding. "Ed," Davis said, "is Max Steiner going to be composing the music score to this picture?" Goulding, surprised by the question, replied that he didn't know, and asked Davis why the matter was important enough to stop the filming of the scene. "Well, either I'm going to climb those stairs, or Max Steiner is going to climb those stairs," Davis responded, "but I'll be God-DAMNED if Max Steiner and I are going to climb those stairs together!"
The scene in Dr. Steele's office where Judith can't light his cigarette, and then a few minutes later, her own, was devised by Edmund Goulding. He explained it as, "When Bette Davis can't light her own cigarette, you know something is seriously wrong with her."
Bette Davis pestered Warner Brothers to buy the rights to the story, thinking it a great vehicle for her. WB studio chief Jack L. Warner fought against it, arguing that no one wanted to see someone go blind. Of course, the film went on to become one of the studio's biggest successes of that year.
Gossip columnist Hedda Hopper was notorious for not verifying her sources. She reported that director Edmund Goulding had engaged Sigmund Freud as technical adviser for "Dark Victory." If she had checked on her scoop, she would have found out that the world's most famous psychiatrist had been dead for several months.