“I do calls every week with my business manager and my lawyer,” he says. “Each week I’m learning something about my business and what I need to know for my career.”

Zack O'Malley Greenburg  | The Forbes Cover Story

Leaning on a soundboard in a Hollywood recording studio, Justin Bieber is about to make me an offer that would prompt instant hysteria among millions of American teenage girls: Do I want to be the first person outside of his inner circle to hear some rough cuts he’s considering for his upcoming album, Believe?

“You’ve gotta hear this, it’s crazy,” gushes the singer. “It’s called ‘Die in Your Arms.’” A moment later his ubiquitous lilt surges full volume from the stadium-quality speakers, a soulful love song reminiscent of early Jackson 5. Next he plays “Happier When We’re Together,” a ballad in which he worries a girlfriend will be unfaithful while he’s on tour. Standing up as his own beatboxing merges seamlessly with a drum machine at the beginning of “You’re the One,” he does an impromptu variation of the Moonwalk.

One can forgive him for the victory dance. Since his debut three years ago Bieber has sold 15 million albums, grossing $150 million on 157 tour dates across two dozen countries along the way. His biopic, Never Say Never, pulled in $30 million on its opening weekend, just shy of the ­concert-film record, and racked up $100 million at the box office in total. His fragrance, Someday, debuted last June and did $60 million in retail sales during its first six months on the market. Those income streams helped Bieber personally earn an estimated $55 million over the past 12 months and $108 million over the past two years.

“You have humans, and you have aliens,” says veteran hitmaker Timothy “Timbaland” Mosley, one of the producers on Believe. “I think he’s half-human and half-alien.”

Even more impressive than Bieber’s earning power: his vast social media reach, part of the reason he ranks third on this year’s Celebrity 100 list. Bieber boasts 21 million Twitter followers—more than any person on Earth not named Lady Gaga. His 43 million Facebook fans are more than Mitt Romney’s and Barack Obama’s put together. With 740 million views, his breakout ballad, “Baby,” is the most-watched video in YouTube history; if you assume three minutes per song, his VEVO channel’s 2.4 billion impressions are enough to provide one minute of video to every person on the planet.

Bieber’s influence and moneymaking talents are fairly well established. It’s far more surprising what he’s doing with that cash. He provides a hint in the dim octagonal recording studio, owned by Rodney Jerkins, who had a hand in many of Michael Jackson’s late-career hits and is now producing songs for Believe. His dancing done, Bieber quickly settles into a chair behind a keyboard. Inspiration has struck: He starts tapping out a fresh beat, as comfortable with the sophisticated equipment as a pop star a generation earlier would be strumming a rhythm guitar. “Can you loop that, what I did?” he asks the engineer at one point. Bieber eventually turns to me: “The tech aspect is just fun for me.”