For Black's Po the panda, a clumsy, tubby behemoth picked by destiny to become a martial-arts master, that meant playing on his strengths, such as using food as an incentive to learn his own variation of kung fu moves.
For chubby funny man Black, the unlikely transition from character roles to leading man required a similar effort to define his own voice and persona on screen.
Before his breakout role as a condescending record-shop clerk in "High Fidelity," he had been more of a mimic than an actor, Black said. His side gig as a member of the music duo Tenacious D changed that.
"I was always trying to kind of imitate the actors that I liked. I was always kind of just doing what I thought the great actors would do," Black said in an interview at the Cannes Film Festival. "And then I kind of found my own voice when I wrote songs and sketches for Tenacious D. I was just being me. I wasn't trying to be somebody else, like John Malkovich or whoever my favorite actor was at the time. And that came through with `High Fidelity' for the first time. It was just me doing my thing, and it's the same thing as this movie. Be your own hero. It makes a lot of sense and resonates with me, because I feel there's a lot of truth to that."
Black, 38, previously dabbled in animation with voices as a tiger in "Ice Age" and a vegetarian shark in "Shark Tale," the latter played as "kind of a nebbishy New Yorker, Woody Allen-type," he recalled.
For "Kung Fu Panda," DreamWorks Animation boss Jeffrey Katzenberg wanted the real Black - his own voice, his own personality. Pitching the story to Black, Katzenberg even had some raw animation of the character prepared with dialogue borrowed from "High Fidelity," Black said.
"It was a fun experience not hiding behind a character voice this time. When you do the character voice, that can be fun and it can inform the character, but you also get distracted by that, and this way, I could just focus on what was funny in the scene," Black said.
"In a way, I feel like this is my most fleshed out and the most satisfied I've been with a role," Black said. "Where a lot of times, on most movies, I have a lot of leftover stuff that I didn't feel I totally nailed as much as I wanted to. I had no regrets on this one, though, no parts where I was like, I wish I could have done this better."
"Kung Fu Panda" directors Mark Osborne and John Stevenson recalled a magazine interview in which Black pondered his childhood in a way that fit the character of Po, a panda toiling in his family's noodle restaurant while sensing he had another calling elsewhere.
Po idolizes ancient China's martial-arts experts, including a tigress (voiced by Angelina Jolie), a viper (Lucy Liu) and a monkey (Jackie Chan). The cast also features Dustin Hoffman providing the voice of the martial-arts master reluctantly teaching Po the moves after the panda is declared a prophesied hero.
In the magazine interview, Black discussed how "he knew he was weird, and he didn't know if he was going to be good weird, but he decided to be the weirdest he could be, so that whichever end of weird he ended up on, he would at least be fully committed to that," Osborne said. "We really wanted to make this a vehicle for him and a way for us to showcase the best part of Jack, which is thematic for the movie. Let him be the best version of himself through this character."
Growing up in Southern California, Black was an artsy kid, drawing, acting and singing. He joined the Actors Gang in Los Angeles founded by Tim Robbins, who cast him in small roles in "Bob Roberts," "Dead Man Walking" and "Cradle Will Rock."
After stealing all his scenes in "High Fidelity," Black grabbed lead roles in such films as "Shallow Hal," "The School of Rock," "Nacho Libre" and "King Kong."
"I would definitely have been satisfied if I could have a career character-actor trajectory," Black said. "Even when I was doing `High Fidelity,' I wasn't thinking, oh, this could be a great steppingstone to getting the lead role in feature films. That was never the goal. Those doors just sort of opened after `High Fidelity,' which was great but definitely beyond my dreams."
Late this summer, Black co-stars as a drug fiend of an actor stuck in the jungle with his cast mates (including Ben Stiller and Robert Downey Jr.) on a war film in the Hollywood spoof "Tropic Thunder," which also features Tom Cruise.
He also co-stars with Michael Cera in Harold Ramis' upcoming "Year One," a comedy set in ancient times.
Black and band mate Kyle Gass played over-the-top versions of themselves in "Tenacious D in the Pick of Destiny," a fictionalized comedy about how their duo came together.
The movie came and went quickly at theaters, with critics finding it unamusing and self-indulgent. Like the band Tenacious D itself, the movie has picked up a bit of a cult audience on DVD, Black said.
"A lot of enthusiastic stoners were like, `Yeah, du-u-u-de! Just saw it!"' Black said. "I was like, `Where were you when the movie came out?' `Sorry, dude, I was hi-i-i-gh!"'
