As far as Jack Black and Dewey Finn are concerned, the actor and the character he portrays couldn’t be more similar or different. Black is the singer, songwriter, guitarist of his own band Tenacious D, and Finn is a singer, songwriter and guitarist of his own band No Vacancy…except they kick him out. And, while rock ’n’ roll is a significant part of Black’s life, rock ’n’ roll is the only thing in Finn’s life.
“I just love the way Mike writes,” admits Black. “Not only does he have that funny edge that suits me, but also he knows how to get into my voice.”
Screenwriter White, who lived next door to Black for three years, had been wanting to write a film geared specifically to Black’s unique personality.

“Jack is a great performer, a terrific musician and the perfect antihero,” says White. “He’s kind of unhinged in that fun way that Willie Wonka is, and I kept having this idea about him jamming around with a bunch of kids.”
With the genius of Black’s stellar comedic style and White’s clever script, “School of Rock” already exceeded the parameters of a traditional comedy, but when the filmmakers recruited director Richard Linklater, they knew they had someone at the helm of the film who could take it even further. Known for such landmark independent films as “Slacker” and “Dazed and Confused,” Linklater also happens to have a penchant for making movies with a heavy influence of rock ’n’ roll.

“I’m a big fan of Jack, both as a musician and as an actor,” says Linklater. “And Jack’s character, a struggling musician willing to do almost anything to help realize his dreams, reminded me of my formative years as a filmmaker.”
“Rick (Linklater) brings reality, honesty and believability to the film,” explains Black. “He reins me in, which is important because I’m always going 10 miles too far over the top. So when I go a little too crazy, he brings me back to reality.”
Not unlike the actor who portrays him, the fiery Dewey Finn is on the verge of exploding throughout “School of Rock.” First, he gives a volatile performance with his band, launching into a long guitar solo and stage-diving into the crowd with no one there to catch him. Next, while masquerading as his roommate, substitute teacher Ned Schneebly (Mike White), Dewey discharges lectures on the wonders of rock and the evils of “The Man” to a wide-eyed class of fifth graders. And finally, in the end, he ignites his students into giving the performance of their lives at the Battle of the Bands.

There to constantly snuff out Dewey’s fuse is straight-laced Rosalie Mullins (Joan Cusack), the always uptight -- unless she’s had a few beers -- principal of the prestigious private school where Dewey is substitute teaching.
“I’m Dewey’s nemesis, and I could blow the whistle on him at any moment,” explains Cusack. “It’s a great role because, down deep, Rosalie Mullins really wants to let loose and be wild. So in a way, I guess she sort of admires Dewey.”
Black, who appeared with Cusack and her brother, John, in the critically acclaimed “High Fidelity,” says working with Joan again was a blast. “She’s very funny,” observes Black. “It was great watching her character crack.”
“Joan is awesome,” agrees White. “She usually plays these sort of blithe spirits, so it’s funny to see her as the uptight, buttoned-down principal. It’s also great to watch her and Jack go at it.”

Rounding out the principal cast with her portrayal of Ned Schneebly’s bossy girlfriend, Patty, is former “Saturday Night Live” writer/comedienne Sarah Silverman, who says that while her role in the film wasn’t comedic, she was glad to play the foil for a change.
“Once I read Mike White’s script, I just had to be in the film,” remembers Silverman. “I don’t usually get to play the ‘bad guy,’ so it was a great chance for me to do something a little different. Besides, let’s face it: If you’re in a film with Jack Black, right from the start you know it’s going to be pretty damn funny.”