At 53, John Debney is one of just a handful of feature film composers today who worked his way up the system, gradually proving himself as an arranger, orchestrator and TV composer. And he may be the only one to have his hair mussed by Walt Disney.

Debney’s father, Louis, was a longtime Disney employee, hired by Walt as a clapperboy in the mid-1930s and eventually becoming a producer on shows such as “Zorro” and “The Wonderful World of Color” in the 1960s. Some of young Debney’s fondest childhood memories are of weekend visits to the studio.

“We’d invariably bump into Walt,” the composer recalls. “He would rough up my hair a little bit. I remember my dad saying, ‘That’s Mr. Disney.’ I grew up in that wonderful extended Disney family.”

Decades later, Debney would be composing music for Disney and every other studio in town, earning an Oscar nomination for “The Passion of the Christ,” three Emmys for his TV music and a BAFTA nomination for “Lair,” his first videogame score. His latest comedy is from Disney: “Old Dogs,” opening Nov. 25.

With more than 70 feature films under his belt, Debney is one of the most prolific composers in the business, with no signs of slowing down. This year his output ranged from “The Stoning of Soraya M.” to “Hannah Montana: The Movie,” and he’s already begun work on next year’s “Iron Man 2” and “Valentine’s Day.”

His enthusiasm for the craft is infectious: “I enjoy the ride,” he says in his comfortable Burbank studio. “I love putting something against the images — being petrified when I’m starting, but one note leads to another, and another, and pretty soon you have something,” he adds with a laugh.

While the volume of work is impressive, so too is the variety through the years. His inspirational score for “The Passion of the Christ” (including choral work in Latin and Aramaic) landed the soundtrack among the Billboard Top 20. And, while Mel Gibson’s 2005 film wasn’t for all tastes, Debney’s music has transcended the controversy with a life of its own.

Debney adapted “The Passion” into an oratorio that he performed live in Rome and then again at the Crystal Cathedral in Garden Grove, Calif., as a benefit for Hurricane Katrina victims. He will repeat the concert June 5 in Rome.

The tumult and Middle Eastern colors of “The Passion,” however, contrast sharply with the warm lyricism of “The Princess Diaries,” the noirish moods of “Sin City,” the country-flavored Americana of “Dreamer,” and the charming holiday music for “Elf.” That versatility was honed in a decade of preparatory training before he got his first big movie break.

“I was very lucky,” Debney says. “Two weeks after I graduated from CalArts, I got into the copying department at Disney. They needed a runner, someone who could paste scores, organize scores. One day (veteran Disney composer) Buddy Baker said, ‘Hey kid, come in here.’ Buddy would give me assignments — arrange this little French song for musette, write a German polka. … They were building Epcot (at Disney World in Florida) and needed a lot of music for different pavilions and rides.”

After three years at Disney, he freelanced for composers like Mike Post (including “The A-Team”) and Hanna-Barbera’s Hoyt Curtin (“Hey Big John! Can you do 10 minutes of ‘Pound Puppies’? Oh, by the way, we’re recording tomorrow!”). He did orchestration jobs, the occasional TV episode and various animation projects, all eventually leading to his own series like the Western “The Young Riders” (1989) and the sci-fi adventure “SeaQuest DSV” (1993), both of which earned him Emmys.

“It was this crazy time of ‘You’d better know what you’re doing or you’re going to learn fast,’ ” Debney recalls. “We’d sketch it and orchestrate it — there were no demos — and ‘See you at the session.’ It was a tremendous training ground. I always got another chance. I don’t think that exists anymore.”

Although he had scored a couple of low-budget features, it was Disney’s 1993 “Hocus Pocus” that proved to be his break into studio films. James Horner dropped out at the last minute, and his recommendation got Debney the job of scoring the lighthearted witch tale in just two weeks’ time. “I benefited from having 10 years of week-in, week-out, very intensive work. By that time I was ready,” he says.

Since then, there has been a stream of comedy films, including two Jim Carrey hits, “Liar Liar” and “Bruce Almighty”; animated films including “The Emperor’s New Groove” and “Chicken Little”; the occasional horror entry (“I Knew What You Did Last Summer”) or fantasy film (“Zathura”); and partial scores to help out friends like directors Robert Rodriguez (“Spy Kids”) and Rob Cohen (“The Mummy: Tomb of the Dragon Emperor”).

“Sure, I do ‘commerce’ movies,” Debney concedes, especially when they involve what he calls “repeat customers” — directors who liked Debney’s previous work for them and return with new projects. But since composing the spiritually meaningful “Passion of the Christ” and this year’s socially conscious “Stoning of Soraya M.,” he says, “what has changed in me is the desire to be involved with great work.”

Debney says he has “no burning desire” to try concert-hall music because he’s so accustomed to writing music designed to accompany visuals. “In the case of ‘The Passion’ or ‘The Stoning,’ sometimes just a tone and a beautiful solo is appropriate. Otherwise, it’s ‘Cutthroat Island,’ you’ve got two battleships, a 100-piece orchestra and choir, and they’re all competing — yet they all find their place and it works. I feel I’m just getting started.”