Dreaming of becoming a hockey star, the Canadian youngster used to practice signing his autograph. Instead, Justin Bieber, 15, is the biggest overnight music sensation of the YouTube era. This fall, he became the first solo artist to place four songs in Billboard's Top 40 before he released his debut album. Now, he'll gladly sign autographs -- if the girls can get close enough.

The 3,000 who showed up to see him last month at a suburban New York mall created such chaos (five girls were injured) that local police canceled the event before he arrived.

Everyone wants a piece of this pop supernova, from the MTV Music Video Awards (where Bieber presented a prize) to "The Today Show" (where he drew the year's biggest audience) and "The Ellen DeGeneres Show" (where he appeared twice in two weeks). Usher and Justin Timberlake both courted the kid to sign a record contract. (Usher prevailed.)

His "My World" album debuted three weeks ago at No. 6. All seven tunes on the CD have landed in Billboard's Hot 100. His videos have racked up more than 100 million views on YouTube. Last month, he opened for Taylor Swift in Europe.

OK, take a breath -- or you'll hyperventilate like one of his fans.

Biebermania has been exploding like the Jonas Brothers did two years ago. The Canadian kid has been the biggest draw for tonight's sold-out KDWB's Jingle Ball (14,000 tickets sold) at Xcel Energy Center.

"He's driving a lot of the bus," said KDWB program director Rob Morris. "He's a teen heartthrob, but his songs do well with over-18 [listeners]. When his songs have been on our 'Newish at Nineish' -- where listeners vote via text or phone -- they have blown the competition out."

He's got a 'swagger coach' now

It all started innocently enough: Two years ago Bieber posted a video of his performance at a Stratford, Ontario, talent contest on YouTube so relatives could see it. (By the way, he finished second, doing Matchbox Twenty's "3 A.M.")

He continued posting homemade videos of songs by Chris Brown, Ne-Yo and Stevie Wonder, and as more people checked them out, things spiraled faster than Brett Favre's passing statistics. Brown even phoned to say how much he liked Bieber's rendition of "With You," shot in what looks like a rec room decked out with hockey pictures and posters of Bart Simpson and Tupac Shakur.

A 27-year-old Atlanta talent manager who'd discovered slacker frat-boy rapper Asher Roth gave Bieber the power-play press, and soon he was recording at Jermaine Dupri's studio in Atlanta.

"One Time" was his official first single on Island Def Jam Records. Its video has garnered more than 17 million YouTube views, with the song peaking at No. 20 on Billboard's Hot 100. Since then, Bieber has released three singles, with "One Less Lonely Girl" rising to No. 16.

His music is the kind of bouncy, bubblegum, puppy-love material that tween girls have been buying for decades, whether it was Frankie Avalon (ask your grandma), Donny Osmond (ask your mom) or Aaron Carter (ask big sister). The difference is that beat-conscious Bieber has not been manufactured by TV or the usual show-biz machine. He's a self-made phenomenon.

He turned 15 in March but looks much younger. His boyish looks and pint-size stature make him appear younger than the teen girls he flirts with in his PG, kiss-on-the-cheek videos. And -- sorry, Jonas fans -- he's cuter than Nick Jonas. Bieber's honey moptop and squinty-eyed glare suggest Zac Efron's younger brother, with Taylor Lautner's nose.

Cute looks, a sweet tenor and A-list songwriters and producers don't guarantee tween success, of course. Bieber's handlers have been subjecting him to finishing school while he's been on tour, performing mostly at radio-sponsored shows.

"I have a swagger coach that helps me and teaches me different swaggerific things to do," Bieber told the Toronto Star last month. "He has helped me with my style and just putting different pieces together and being able to layer and stuff like that."

Or, as swagger coach Ryan Good, 24, told the Toronto paper: "Usher called me and said he thought Justin would benefit from being around a cool white boy."

R&B superstar Usher joins manager Scott (Scooter) Braun and industry heavyweight Antonio (L.A.) Reid as executive producers of Bieber's album. Usher even makes a cameo in the video of "One Time" and on the song "First Dance."

"He's like a big brother to me," Bieber said of Usher. "We just hang out and don't really talk about music a lot. We go go-karting and to arcades and movies."

Usher thinks Bieber has that hard-to-define star quality. "He just had that thing -- the 'It,'" the superstar told Entertainment Weekly. "He's very charismatic. He knows how to charm a room."

Canada's biggest pop star was too busy traveling, charming the world -- and breaking his foot in a Nov. 23 concert at London's Wembley Arena -- to get on the phone with the Star Tribune. Sigh. But an Internet search indicated that he is fond of saying "This is crazy."

'Never tried to get famous'

Growing up with his single mother in Stratford (midway between Toronto and Detroit), Bieber played soccer and hockey. He also showed an aptitude for music.

"When he was 5, he'd hear something on the radio and go to the keyboard and figure it out," his mother, Pattie Mallette, told Entertainment Weekly.

It was not an easy life, with mom working two jobs. "We were living below the poverty line," said Mallette, who has remarried and has a 2-year-old daughter. "We had a roof over our heads and we had food in the house, but we really struggled."

To Bieber, though, it was "a regular kid life. Pretty normal," he told the Waterloo (Ontario) Region Record.

He learned how to play keyboards, guitar, trumpet and drums.

"I would always just sing around the house and play instruments, but I never tried to get famous," said the kid, who had Boyz II Men posters on his bedroom walls.

Now, of course, he is ridiculously famous. So famous that after the near-riot Nov. 20 at a Long Island mall, he told WBLI radio: "It was so crazy that I couldn't get to even come in the building. They basically threatened to put me in cuffs and send me away to jail."

Take a breath, Justin. The craziness is only beginning.

Jon Bream • 612-673-1719