Actor Mark Ruffalo poses during the 2014 Sundance Film Festival, January 19, 2014 in Park City, Utah.
Nominated for an Academy Award (for "The Kids Are All Right") and a Tony (for "Awake and Sing!"), Ruffalo has become known for his extraordinary range - playing a disgraced music executive in "Begin Again," a gay activist in "The Normal Heart," a hulking superhero in "The Avengers."
By CBSNews.com senior producer David Morgan
This Was His Youth
Born in Wisconsin, Mark Ruffalo took up acting in his senior year at high school. He later studied at the Stella Adler School of Acting in Los Angeles.
"It was a three-year program and I ended up staying for six years," Ruffalo told CBS News' Anthony Mason. "I was working on my craft, man!"
By his own count, he went to more than 600 auditions before he broke through in 1998, in the Broadway play, "This Is Our Youth."
Mark Ruffalo (with correspondent Anthony Mason) at L.A.'s Good Luck Bar, where - as an aspiring actor - he had tended bar for a time. He even had a drink named after him: A "Markarita."
"You Can Count on Me"
"This Is Our Youth" led to Ruffalo playing the role of Laura Linney's troubled brother in Kenneth Lonergan's 2000 film, "You Can Count on Me."
"And all these casting directors were like, 'Where did you come from?'" said Ruffalo. "I'm like, 'What are you talking about? I've been under your noses for the past 10 years! Where have you been?'"
Ruffalo received the Los Angeles Film Critics Association's New Generation Award for his performance.
Ruffalo & Paltrow
Top: Mark Ruffalo with Gwyneth Paltrow in the 2003 romantic comedy "View From the Top."
The two shared the screen together again in the 2012 comedy, "Thanks for Sharing" (below) - and are also joined in the Marvel Universe as Dr. Bruce Banner and Pepper Potts.
But just as the things were breaking Ruffalo's way, doctors discovered a brain tumor. It proved to be benign, but the surgery to remove it left one side of his face paralyzed.
"It lasted a long time. It lasted to the point where they were saying, 'You're probably not going to get your face back."
Ruffalo slowly recovered – and fought his way back, winning roles in "Collateral" (left), "Eternal Sunshine of the Spotless Mind," and "13 Going on 30."
Mark & Sunrise
Mark Ruffalo attends the premiere of his film, "13 Going on 30," with his wife, actress Sunrise Coigney, at the Mann Village Theater on April 14, 2004 in Los Angeles.
"In the Cut"
Mark Ruffalo and Meg Ryan in Jane Campion's 2003 murder mystery, "In the Cut," costarring Jennifer Jason Leigh.
"We Don't Live Here Anymore"
Mark Ruffalo, Peter Krause, Naomi Watts and Laura Dern in the 2004 drama, "We Don't Live Here Anymore."
"All the King's Men"
Jude Law, Kate WInslet and Mark Ruffalo were among the cast of Steven Zaillian's 2006 remake of "All the King's Men," which also starred Sean Penn, James Gandolfini and Patricia Clarkson.
Mark Ruffalo played a San Francisco police detective opposite Robert Downey Jr.'s newspaper reporter in David Fincher's 2007 film "Zodiac," based on the true story of the infamous "Zodiac" murders in the 1960s and '70s.
Mark Ruffalo and Joaquin Phoenix in the 2007 drama, "Reservation Road," about an attorney trying to cover up his role in a hit-and-run fatality.
"The Brothers Bloom"
Adrien Brody, Rachel Weisz and Mark Ruffalo in the 2008 comedy "The Brothers Bloom," by writer-director Rian Johnson ("Looper").
Mark Ruffalo and Leonardo diCaprio in Martin Scorsese's 2010 thriller, "Shutter Island."
"Sympathy for Delicious"
Mark Ruffalo's directorial debut, "Sympathy for Delicious," about a paraplegic who becomes a sometimes-successful faith healer, won the Special Jury Prize at the 2010 Sundance Film Festival.
"The Kids Are All Right"
Grieving the death of his brother, Scott Ruffalo, whose murder in Beverly Hills was never solved, Ruffalo moved with his family to a farm in Upstate New York and was considering a career change when he took a part in Lisa Cholodenko's "The Kids Are All Right," playing a sperm donor to two lesbian parents, played by Julianne Moore and Annette Bening.
"It was gonna be my last thing," Ruffalo told CBS News' Anthony Mason. "I didn't know if I would ever act again. I was like, 'You know what? I'm done with that part of my life for a while. I want to direct. I want to write.' And I knew going in that that was going to be what it was. And I had such a good time -- I was free.
"And then all of a sudden the movie became what it became" - a Best Picture nominee. Ruffalo himself received an Oscar nomination for Best Supporting Actor.
Actress Sunrise Coigney and actor Mark Ruffalo arrive at the Golden Globes After-Party at The Beverly Hilton hotel, January 16, 2011 in Beverly Hills, California.
What followed "The Kids Are All Right" may the most unexpected role of Ruffalo's career: The part of Dr. Bruce Banner in "The Avengers."
"They really reached out and expressed interest, and I said, 'Oh, come on!'" he told Anthony Mason. "'Cause I just didn't really see myself in that world."
And then "Iron Man" himself, Robert Downey Jr. (who'd starred with Ruffalo in "Zodiac"), called. "And I said 'What do you think?' He said, 'We got this. Come on. Let's do this. We got this. It's gonna be great, Ruffalo!'"
So great, he is reprising the role in the 2015 "Avengers" sequel, "Age of Ultron."
In Kenneth Lonergan's "Margaret," Mark Ruffalo played a bus driver who is pursued by a young girl (played by Anna Paquin) who feels complicit in a fatal accident.
"Now You See Me"
Mark Ruffalo plays an FBI agent with a secret, opposite ex-magician Morgan Freeman, in the caper film "Now You See Me" (2013).
"The Normal Heart"
Adapted from Larry Kramer's play, the 2014 HBO film "The Normal Heart" starred Mark Ruffalo as AIDS activist Ned Weeks, fighting to raise awareness about HIV during the early years of the epidemic.
The film, which costarred Taylor Kitsch and Julia Roberts, won the Emmy Award for Outstanding TV movie. Ruffalo and Roberts were among the six actors nominated.
People's Climate March
Actor Mark Ruffalo participates in the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, was organized by a coalition of unions, activists, politicians and scientists.
Mark Ruffalo plays a washed-up music producer who believes an aspiring songwriter (Keira Knightley) has the goods for a successful record in the 2014 film "Begin Again," written and directed by John Carney ("Once").
A rooftop recording session in "Begin Again," featuring Mark Ruffalo and Keira Knightley.
"Foxcatcher" follows the tragic true story of wrestling's Schulz Brothers, Dave and Mark (played by Channing Tatum), both Olympic champions, who fall under the eerie influence of millionaire John duPont (played by Steve Carell).
Ruffalo, who wrestled in high school, says it was the most physical role he's ever had. "Oh yeah, it was tough," he said. "I was in a lot of pain. I hurt myself a lot."
Cannes Film Festival
From left: Mark Ruffalo, Channing Tatum, director Bennett Miller, Steve Carell, and producer Megan Ellison attend the "Foxcatcher" premiere during the 67th Annual Cannes Film Festival on May 19, 2014 in Cannes, France.
"Infinitely Polar Bear"
Mark Ruffalo stars in Maya Forbes' "Infinitely Polar Bear," about a bipolar, unemployed father trying to take care of his two children on his own as his wife (Zoe Saldana) leaves to attend grad school.
Actors Jeremy Renner, Mark Ruffalo and Chris Hemsworth are seen onstage at a panel for "The Avengers: Age Of Ultron" during Comic-Con International 2014 at San Diego Convention Center at on July 26, 2014 in San Diego.