Monteith, who turned 31 on May 11, starred in "Glee" as a high school football player who puts his status and popularity at risk to join the glee club and its outcast members.
The show, with its pop music-based song-and-dance numbers and high-profile guest stars including Gwyneth Paltrow, became an immediate hit and made stars of its relatively unknown cast.
The series, which debuted in 2009, is in its fourth season.
On his Twitter account, Monteith described himself as "tall, awkward, canadian, actor, drummer, person."
He had recently shot a Canadian film called "All the Wrong Reasons," slated to be released later this year with actors Kevin Zegers, Karine Vanasse and Emily Hampshire.
In a 2010 interview with The Associated Press, Monteith was upbeat about life. He said that if "Glee" were to be canceled he would be OK.
"I've never been afraid of working," he said. "I've never been afraid of auditioning for jobs. Obviously, I've never been afraid of anonymity. I was happy (before 'Glee'). I'm happy now. I guess I'm well adjusted."
Monteith was among the "Glee" actors who remained series regulars as their characters graduated high school and moved on to other adventures. However, in real life Montieth dropped out of high school in Vancouver after his parents divorced.
According to his biography on Fox's website, Monteith was born in Calgary, Alberta, and moved to Vancouver Island as a child. Before turning to acting, he held a variety of jobs including Wal-Mart greeter, school bus driver, roofer and cab driver.
"Thanks for always being kind Cory. You came a long way from hanging on the beaches in Vancouver with the gang pre-Glee," tweeted Gerard Funk, an actor from Vancouver who joined the "Glee" cast last year.
Monteith's TV credits included roles on the series "Kaya" and "Kyle XY" and guest appearances on "Smallville," ''Supernatural," ''Stargate," ''Flash Gordon" and "Interns." His film credits included "Final Destination 3," ''The Invisible," ''Deck the Halls" and "Whisper."
His big break came when he submitted an audition tape to the "Glee" producers in Los Angeles and then raced straight down the Pacific Coast in his car from Vancouver when he was invited to meet them in person.
"I nailed it. I knew I nailed it," Monteith recalled about his audition in an interview with Canadian TV columnist Bill Brioux. "When you walk in to the room, the heads of Fox ... of course it's a little unnerving. Then you realize they're all waiting for you. It's kind of flattering in a way."
Monteith was an avid supporter of Project Limelight, a Vancouver charity that offers a theater and arts programs to at-risk youth. He dined with Project Limelight co-founder Maureen Webb at a Vancouver restaurant just days before his death.
In a Globe and Mail interview last year, Monteith credited Webb for suggesting that he enroll in acting classes when he was 19 years old and going down a "very dark path."
He kept in touch with Webb and made a video to support Project Limelight when the charity was launched last year.
"I think kids really need a place to go and feel like they belong," Monteith said in the video posted on Project Limelight's website. "When I was a kid, I struggled a lot with who I was and where my life was going and what I was interested in. And I was fortunate to have the arts inspire me."
Outside Vancouver hotel, fans paid tribute to Monteith by leaving notes, flowers and stuffed animals.
Helen Slater, 16, who was visiting from England, said she was shocked to hear about his death as she placed a note and a stuffed moose because he had once been photographed wearing moose antlers. She called him a "positive influence" and said "Glee" helped change her life.
"Nothing's going to be the same anymore," she said. The show "just put me (through) some really tough times, and helped me through depression a lot."
Elber reported from Los Angeles. Associated Press writers Charles J. Gans and Frazier Moore in New York and Derrik J. Lang in Los Angeles contributed to this report.