In the film, Snowbell is very protective of certain family members, mostly Stuart.
In the novel, Snowbell is the malevolent, self-absorbed, negative, obstinate, witty, bellicose, evil, loathsome, loquacious, testy, ingenious, narcissistic, kooky, eccentric, relentless, boorish, emotional, loud-mouthed and loco family cat. In the film, Snowbell is seen as a friendly, shy, selfless, nurturing, optimistic, well-behaved, benevolent, even-tempered, loyal, level-headed, thoughtful, imaginative, nice, kind-hearted, efficient, respectful, big-hearted, empathetic, laid-back, low-key and lovable coward. He often focuses first and foremost on his own needs and frequently gets in trouble as a result.
In the novel, after Stuart gets caught in the window, Snowbell places Stuart's hat and cane near the mouse hole, panicking the family. Later, Snowbell attempts to eat Margalo, but Stuart shoots Snowbell's ear with the arrow. Later, Snowbell told one of his friends, the Angora cat, about Stuart and Margalo. After Margalo's disappearance, the Little family questioned him closely.
In Stuart Little, Snowbell despised Stuart at first and lunged to eat him shortly after he arrived at the Littles' house and looked at the pictures. This prompted Stuart's parents to scold Snowbell and demand that he spit Stuart back out (to which he does), and Frederick picks Snowbell up and sternly tells him that he should not eat Stuart. He eventually becomes very caring for Stuart and redundantly agrees to tag along with him to fight the Falcon and save Margalo.
- Snowbell is the secondary antagonist-turned-tritagonist of Stuart Little, the deuteragonist of Stuart Little 2, a recurring character of Stuart Little: The Animated Series and the tritagonist of Stuart Little 3: Call of the Wild.