He first appears in the short Plutopia. In the short, Mickey and Pluto go off on vacation at a wilderness lodge. Milton was a stray that was briefly chased by Pluto upon their arrival. That night, Pluto was forced to sleep out with a muzzle due to rules so Milton took the opportunity to steal Pluto's dinner having him rest starving. In Pluto's dream; Milton is his loyal servant that enjoys being bitten on the tail by Pluto. Eventually after Pluto awakens he bites Milton on the tail expecting dinner but as a result, a fight takes place.
In 1950, he appeared in the Pluto short, Puss Café along with 2 other cats trying to steal food while trying to avoid Pluto.
Later Milton appears in the 1951 Pluto short, Cold Turkey. In this short, he and Pluto are asleep while the television plays wrestling. Soon, a commercial comes on about turkeys, the cat wakes up and is smitten by the commercial. He wakes up Pluto, then the two proceed to search for a turkey throughout the television entertainment system. Failing at that, they then search in the kitchen. After falling in a trash can, the cat gets the idea to have Pluto launch the cat into the air to the cabinet above, using the trash can. After many failed attempts, the cat is launched to the refrigerator, which he then opens. Finding the turkey, the two then battle it out for the poultry. Eventually, the cat ends up inside of the television with the turkey, while Pluto devilishly turns it on, crating head inside the set. The cat is launched out of the television, but the turkey is burnt to ash. The two then start to play fight, as the short ends.
Decades later, Milton would make his first appearance since Cold Turkey in the video game Epic Mickey. Milton makes a cameo appearance in the Plutopia based mini-level.