The fresh-faced pop singer also won statuettes for favourite pop album, breakthrough artist and favourite male pop artist.
Since the awards are determined by fans online voting, the 16-year-old star was unquestionably the frontrunner. His millions of young female fans reportedly account for a hefty portion of overall Twitter messaging traffic.
Eminem and country trio Lady Antebellum, who led the contenders with five nominations each, had to make do with some scraps. Eminem won a pair of prizes in the rap/hip hop field, losing to Bieber in his three other categories. He did not attend the event at the Nokia Theatre. Lady Antebellum was named best country group. R&B singer Usher, who helped discover Bieber about 18 months ago and signed the youngster to a record deal, also won a pair of prizes.
The two embraced on stage after Bieber collected his artist of the year trophy. I dont cry that often but I did, and I enjoyed it, Usher told reporters backstage.
During his trips to the stage, Bieber repeatedly thanked his fans and reflected on his unlikely rise to fame. Im from the smallest town in the world of, like, 30,000 people, he said as he accepted the breakthrough artist award. I never thought this was possible.
Bieber, who was raised in Stratford, Ontario, but now lives in the United States, is perhaps the hottest new commodity in the music world.
His album My World 2.0 has sold almost 2 million copies in the United States since its release earlier this year, and his public appearances turn into mob scenes.
It ended up being a great night for Canadians. Michael Buble, 35, won his first-ever award, for favourite adult contemporary artist. While you Americans are sitting getting fat, us Canadians are getting ready to take over, he joked backstage.
British rock band Muse was also a first-time winner, for favourite alternative rock artist. Other winners at the 38th annual ceremony included country stars Taylor Swift, Carrie Underwood and Brad Paisley; funk band the Black Eyed Peas; R&B singer Rihanna, and Colombian pop siren Shakira.
Backstreet Boys Nick Carter said hes honored to share a stage with his musical forefathers. We appreciate and respect everything that these guys have done for the music industry, and now its just great to be together. I think thats whats awesome.
You know whats awesome, Nick? Your teaming up with NKOTB is the modern equivalent of Messrs. McCartney and Jagger deciding that there might be interest in The Beatles and Rolling Stones doing something similar. Except NKOTBSB can bring dance routines and way better hairlines into this particular equation. NewsFeed, along with the rest of the enraptured world (that includes you, Bieber) will hold onto its hat and declare that the boy band is well and truly dead, replaced by the man band. Resistance, as always, is futile.