What kinds of backstage pleasures does a newly minted heavy-metal star enjoy these days? At the Winter Garden Theater, Alex Brightman, the lead actor of Broadway’s “School of Rock,” has furnished his diminutive dressing room with such not-so-hedonistic gratifications as a steam-inhaler mask, tasteful throw pillows and a collection of year-end award-season movies on DVD.

Even the colorful contents of his pill case are not nearly as illicit as they might seem: “They’re all vitamins,” Mr. Brightman said recently as he gulped down a bitter handful. “It’s all to make me superhuman on the inside.”

Mr. Brightman, 28, who has cultivated a burly, bearded, Belushi-esque look for “School of Rock,” hardly fits the stereotype of a preening, Spandex-clad guitar god. But he has nonetheless turned this musical, which is based on the 2003 Jack Black comedy and opened last month, into his personal stairway to heaven.

In a production whose creative team includes the composer and producer Andrew Lloyd Webber, and whose cast is populated with precocious tween-age musicians, Mr. Brightman, a steadily employed if relatively unknown Broadway performer, could have been easily overshadowed.