An animation veteran while still relatively young, Trousdale took a slightly less direct route to glory in the Disney animation department than some of his contemporaries. Nonetheless, he would go on to co-direct "Beauty and the Beast" (1991), a landmark in the history of the medium. A product of the innovative character animation program at the Disney-sponsored California Institute of the Arts (CalArts), Trousdale found full-time work as an animator while in his third year. However, unlike such fellow alumni as John Lasseter ("Toy Story") and Henry Selick ("James and the Giant Peach"), he did not go directly to Disney. Instead, Trousdale spent a year at Carter/Mendez Productions where he animated, designed and storyboarded various TV projects including "Stanley, The Ugly Duckling" (ABC, 1982), a presentation of the "ABC Weekend Specials". Trousdale next worked for Grand American Fare, doing illustrations and paste-ups for restaurant menus, special event flyers and tee shirts. Trousdale's fortunes began to change when he was hired by Disney.

Trousdale debuted at Disney working in animated special effects. He was an "in-between effects artist" on the unsuccessful animated feature "The Black Cauldron" and an assistant and clean-up effects animator on the live-action teen film "My Science Project" (both 1985). Trousdale gained attention around the studio with a series of "bad attitude" gag cartoons. This led to him being transferred to the feature animation division's story development department. Trousdale received his first feature credit as a storyboard artist on the breakthrough musical animated hit "The Little Mermaid" (1989).

Trousdale segued to cartoon direction with "Cranium Control" (1989), a four-minute animated pre-show for the "Wonders of Life" exhibit at Disney's Epcot Center in Florida. This short was also notable as his first directing collaboration with Kirk Wise. (The pair had worked together previously on story development for a Roger Rabbit cartoon.) They also received story credits on the innovative computer animated short "Oilspot and Lipstick" and the features "Oliver & Company" (1988) and "The Lion King" (1994). Trousdale and Wise also shared storyboard credits on the Mickey Mouse short "The Prince and the Pauper" and the feature sequel "The Rescuers Down Under" (both 1990). Their shared background in story served them well in their directing efforts. With complementary abilities in animation--Trousdale's forte being special effects and layout and Wise's being character animation and acting--the pair proved a formidable team. Together they made their feature directing debut on "Beauty and the Beast", a critical and commercial success which became the first animated feature to be nominated for an Oscar for Best Picture.

Not only did "Beauty and the Beast" gain new respect for animated features in Hollywood, but it also demonstrated that the musical could still be a viable commercial genre. (It even generated a hit Broadway musical spin-off.) That each of the six musical numbers either revealed character or advanced the plot certainly contributed to the film's success. Just as important were the vibrant, well-defined characters and the artful use of developing CGI (Computer Generated Imagery) technology. Trousdale and Wise displayed similar strengths in their next directing collaboration, "The Hunchback of Notre Dame" (1996), a kinder, gentler, musical take on Victor Hugo's oft-adapted 1931 novel.