Roquefort is a small mouse who resides in a mousehole located in Madame Bonfamille's mansion. He is good friends with Duchess, a female cat, and her three kittens, Toulouse, Berlioz, and Marie; he also seems to have a friendly relationship with Frou-Frou. His devotion to the Aristocats is shown when he goes out searching for them when the family goes missing.
Despite being on friendly terms with Duchess and her kittens, he seems to be naturally afraid of other cats, though he places this fear aside to assist his friends.
Roquefort is introduced as Duchess and her kittens are preparing to eat the special dinner Edgar has prepared for them. Roquefort is invited to dinner by the kittens and produces a cracker he had brought with him, dipping it into the milk. Unknown to any of them, Edgar laced the milk with sleeping pills, and Roquefort is knocked unconscious as he tries to return to his mouse hole for another cracker.
After hearing that Duchess and her kittens are missing, he spends all night searching the streets of Paris for them but is unsuccessful. He reports to Frou-Frou to tell her the sad news. Edgar suddenly walks in the stable with an unusually cheerful grin, and Roquefort deduces that Edgar was responsible for kidnapping Duchess and her kittens after overhearing him gloating over his making the headlines (specifically, referring to his using the bike to abandon the cats into the wild).
Later, Roquefort tries to hitch a ride on Edgar's motorcycle, but gets bumped up and down several times and coughs up smoke that was blown at him before he is flung off of the motorcycle and into the street.
When the cats do return, he notices Edgar and ties his shoelaces together, causing the butler to trip. This gives Roquefort some time to warn them. However Duchess and her kittens are unable to hear him through the glass window and mistake his frantic arm and leg gestures for being pleased to see them. The cats enter the house, but before Roquefort can warn them again, the butler catches them in a sack and locks them in an oven with plans to mail the cats to Timbuktu.
At Duchess's request, Roquefort manages to find O'Malley, the alley cat who had guided the family back to Paris. However, because the oven grate was closed and thus blocked out their words, Roquefort misheard and thought they called him some other name. O'Malley immediately heads toward the mansion. He tasks Roquefort with rounding up Scat Cat's gang of Alley Cats. Roquefort reminds O'Malley that he is a mouse, but O'Malley tells Roquefort that the cats will not harm him if Roquefort gives O'Malley's name.
Roquefort meets up with Scat Cat and the alley cats and tries to get them to help, but is unable to remember O'Malley's name and is forced to take cover inside a bottle. The alley cats prepare to eat him, but Roquefort yells out the proper name in frustration when asked for last words. The alley cats apologize to Roquefort and immediately leave to help O’Malley and Duchess, leaving Roquefort to chase them down in an attempt to lead them to the correct house. Coincidentally, this also led to a Frenchman to consider giving up drinking wine after he witnessed a mouse (Roquefort) seemingly chasing the cats. Believing he was hallucinating, the Frenchman poured his wine onto the ground.
During the resultant fight between the alley cats and Edgar, Roquefort attempts to release Duchess and her kittens from the trunk that Edgar has imprisoned them in by cracking the combination lock, abruptly yelling for silence in order to hear better, causing everyone to freeze mid-fight. Meanwhile Edgar takes the cats' place inside the trunk and is sent to Timbuktu himself. After Edgar is defeated, Roquefort remains in Madame Bonfamille's home with the cats. When Madame Bonfamille is about to take a photo of the cats, she tells them to "say cheese", at which Roquefort comes out of his mouse hole eagerly. He is last seen conducting Scat Cat and his band to the song, "Everybody Wants to Be a Cat".
- Roquefort's name seems to come from a particular kind of sheep's milk cheese that is made in the southern portion of France.
- Roquefort's coughing noises were recycled sounds from Archimedes in The Sword in the Stone.
- In the storybook LP record soundtrack of the movie, Roquefort mentions his hero is Sherlock Holmes, hence his detective clothes.
- While Roquefort doesn't appear in the 2006 book, "Disney's Marie" by Kitty Richards, he becomes a father and has a son named "Roquefort Jr.". Roquefort Jr. has a similar appearance to Roquefort with the only difference being his fur color and shorter nose. Roquefort Jr. serves as Marie's travel companion and bodyguard in the book.
- Roquefort is the protagonist of the 1983 book "The Aristocats and the Missing Necklace". Marie, Toulouse, and Berlioz serve as Roquefort's travel companions as they search for Duchess's missing necklace.
- Like Madame, Roquefort usually refers to the kittens as “kittens”. Unlike Madame, however, (who briefly refers to Marie and Toulouse by their names at the beginning of the film) Roquefort has never called any of the kittens by their names.
- In Disneyland Records, Roquefort is the narrator and he mentions each of the kittens’ names.