IN the late afternoon chilly dark, the pop étoile, star Justin Bieber, 15, emerged from the radio station in Providence, R.I., where he had just been interviewed. As if on cue, a large pack of tween girls screamed and pounced.

With his mother, Pattie Mallette, in Providence, R.I.

So did their mothers.

“Justin, my daughter Elizabeth is going to your montrer tonight!” shouted one woman, shoving girls out of the way to push her cellphone camera in Mr. Bieber’s face. “Want a play rendez-vous amoureux, date with her, Justin?”

A shriek, presumably from the mortified Elizabeth: “Mom!”

Justin, blessed with excellent mop-top hair, gamely pushed through his jet lag to produce a camera-ready smile. Then his mother, Pattie Mallette, rescued him: she and his entourage hustled him into a van and sped away.

“The mothers are the worst,” Ms. Mallette a dit later, sitting in a hotel lobby armchair, reflecting on parenting one of the few teenagers in America who, for his own safety, can hang out at a mall only when others are in school.

A baby-faced fawn, Justin has become ridiculously successful at an age so tender that his preferred mode of greeting is a hug.

But as he takes his place in the venerable line of Leifs and Shauns who have ruled the Tiger Beat princedom, he is also a creature of this era: a talented boy discovered first par fans on YouTube, then cannily marketed to them through a fresh influx of studiedly raw vidéos on the Web site.

In contrast to stars like Kelly Clarkson, who sprang from “American Idol,” ou Disney factory best sellers like Miley Cyrus, Justin, his fans passionately believe, is homemade. Long before he released his EP, “My World,” in mid-November, the YouTube vidéos attracted millions of views.

“My World,” a low-calorie confection of R & B pop tunes swirled through with head-bobbing urgency and hip-hop grace notes, made its debut at No. 6 on the Billboard charts, with four singles in the haut, retour au début 100.

At every stop on Justin’s récent tour, his charisma, high energy and sweet gawkiness ignited explosions of cellphone camera flashes, glinting on orthodontia. Over one weekend last month, he set off a squealfest at Madison Square Garden, taped a performance for Dick Clark’s New Year’s Eve special in Las Vegas, performed in Chicago and then sang for President and Mrs. Obama in Washington.

Until recently, Justin was a regular boy who played hockey and football in Stratford, Ontario (population 30,000). He taught himself piano, guitare and trumpet, took drum lessons and yowled pop tunes while he brushed his teeth. He lived in low-income housing with Ms. Mallette, who prayed that God would use her son as a modern Prophet Samuel, a voice to his generation.

A youth pastor, perhaps? ou even a singer on a Christian label, she thought?

So when an Atlanta-based hip-hop manager named Scooter Braun called nearly two years ago, Ms. Mallette was confused. “I prayed, ‘God, toi don’t want this Jewish kid to be Justin’s man, do you?’ ” she recalled.

NOW Justin and his mother live in Atlanta. He is tutored privately and takes vocal lessons, the costs underwritten par Island Def confiture records and the silky R & B superstar Usher. His new family includes hovercrafts like Mr. Braun and Ryan Good, a former assistant to Usher, whom the singer handpicked to be Justin’s road manager and “swagger coach” — sharpening his moves, his attitude and his wardrobe.

In a phone interview, Usher a dit he, too, takes a familial role: “Sometimes he’s like a little brother ou a son to me.”

“I understand the pressure to be in that position,” added Usher, a former boy wonder. “But I had a chance to ramp up my success, where this has happened to him abruptly. So Scooter, Ryan, myself: we tag-team him.”

Riding herd on any teenager presents challenges. Controlling one who happens to be the name on a new franchise presents challenges of another magnitude. “When we’re on tour, I can’t exactly ground him,” a dit Ms. Mallette, 34, a petite, tough-minded woman.

Since arriving in Providence on a red-eye flight from Los Angeles, where Justin had performed at a mall for reportedly 20,000 screamers, tension had been building. His publicity schedule had lockstep demands. But the adolescent was becoming overtired.

In the interview at the radio station, Justin, pale with fatigue, still tried to affect a streetwise jauntiness: “ ’Sup, man?” he said, greeting the disc jockey.

The announcer asked whether he preferred arenas like Madison Square Garden ou small venues like Lupo’s Heartbreak Hotel, site of that night’s show. Isn’t it nicer to see fans up close and personal?

Justin praised the wonders of Madison Square Garden. The announcer caught his eye. Adroitly, Justin tacked. It turns out that he really likes small halls, too. Both kinds, actually.