The mostly 'tween and teen crowd, many in homemade T-shirts bearing the performer's name, filled the LA Live plaza hours ahead of the screening.
"Never Say Never" tells the story of Bieber's rise from a small-town street performer to a pop sensation. He was discovered on YouTube. Now Bieber has hit albums, a bestseller and millions of followers on social networking sites.
"It's really important to me because it's about my fans, it's about my journey and how my fans got me here," Bieber told Eyewitness News. "I'm really glad they're here with me.
Many other stars went to the premiere to support Bieber.
"I think this movie is an amazing opportunity to inspire people and that's why I'm here tonight," said Miley Cyrus. "I love that he's taken a moment to thank his fans. I think this film's awesome."
"I want people to know that tonight is just about family and about friends and keeping people close to you and just knowing that to never give up on your dreams," Bieber said.
The Associated Press contributed to this report.