Made her way into film history as the little girl accidentally drowned by the Frankenstein monster (as played by Boris Karloff) in the 1931 film "Frankenstein".
After several takes of Harris's being thrown into the water by the monster in "Frankenstein," it was discovered that one last take was necessary, and director James Whale promised Marilyn, a good swimmer, anything she wanted if she would do the take one more time. She asked for her favorite snack: one dozen hard-boiled eggs. Whale gave her two dozen.
According to Harris, she was adopted by an overbearing stage mother.
Harris learned later that she had appeared in an undetermined Rin-Tin-Tin movie when she was only one month old.
During production of Frankenstein (1931) there was some concern that seven-year-old Marilyn Harris, who played Maria, the little girl thrown into the lake by the creature, would be overly frightened by the sight of Boris Karloff in costume and make-up when it came time to shoot the scene. When the cast was assembled to travel to the location, Marilyn ran from her car directly up to Karloff, who was in full make-up and costume, took his hand and asked "May I drive with you?" Delighted, and in typical Karloff fashion, he responded, "Would you, darling?" She then rode to the location with "The Monster.".