After 12 years as a struggling actor, Mark Ruffalo became the next big thing with his exceptional performance in the Oscar-nominated independent film You Can Count on Me (2000). Wisconsin-born Ruffalo wanted to be an actor as a child, but he ignored his early aspirations until the end of high school. Not sure what else to do, Ruffalo headed to Los Angeles at 18 "out of desperation" to study the craft at the prestigious Stella Adler Conservatory. After taking classes for several years and evading career decisions, Ruffalo began to venture into L.A. theater and independent film. Along with acting in over 30 plays, as well as writing and directing one of his own theater works, Ruffalo spent the 1990s amassing roles in indie movies, beginning with A Gift From Heaven (1994). Working mostly in comedies, Ruffalo appeared in The Last Big Thing (1996) and alongside comic character actor stalwarts Steve Zahn and Paul Giamatti in Safe Men (1998); he also starred as an artist with love problems in the romantic comedy Life/Drawing (1999). Trying his hand at screenwriting, Ruffalo penned Slamdance success The Destiny of Marty Fine (1996). Two potentially higher-profile films, the disco period film 54 (1998) and Ang Lee's Civil War epic Ride With the Devil (1999), failed to make a positive impression on critics and audiences. Ruffalo's luck began to change, however, when he was cast in an off-Broadway production of This Is Our Youth. Not only did he win an acting award, but Ruffalo also got to know the playwright, Kenneth Lonergan. Despite his non-resemblance to future onscreen sister Laura Linney, Ruffalo talked Lonergan into auditioning him for the role of Linney's brother in Lonergan's first film, You Can Count on Me. Well-matched in familial chemistry, Ruffalo's self-destructive, irresponsible, sensitive Terry meshed perfectly with Linney's uptight Sammy and her sheltered son, Rudy (Rory Culkin), creating a deeply felt portrait of troubled yet strong family bonds. Earning raves for its nuanced performances as well as sharp writing, You Can Count on Me garnered Ruffalo the Montreal Film Festival's Best Actor prize and talk of an Oscar nod. Though he didn't get the nomination, Ruffalo swiftly moved up the Hollywood ranks, starring as an imprisoned military pilot caught between Robert Redford and James Gandolfini in The Last Castle (2001), and as a soldier in John Woo's WWII saga Windtalkers (2001). Ruffalo's ascent to stardom was temporarily sidetracked, however, when he was diagnosed with a brain tumor while filming The Last Castle in 2000. Forced to drop out of the Joaquin Phoenix role in M. Night Shyamalan's summer hit Signs (2002), Ruffalo had surgery and spent months rehabilitating from the procedure. Having made a full recovery, Ruffalo returned to work. After Ruffalo appeared as Gwyneth Paltrow's boyfriend in the woeful flop View From the Top (2003), his lead performance as the male axis of a complicated love triangle in the indie film XX/XY (2003) garnered far more enthusiastic critical kudos than the movie itself. Ruffalo also stayed firmly within the independent cinema realm, co-starring as terminally ill Sarah Polley's lover in the drama My Life Without Me (2003). Ruffalo subsequently scored roles in two higher-profile, if still offbeat, Hollywood projects. In Jane Campion's long-gestating adaptation of erotic thriller In the Cut (2003), Ruffalo co-starred as a homicide detective who becomes involved with Meg Ryan's lonely New York professor. 2004 started off with a bang for Ruffalo when We Don't Live Here Anymore, a film he both starred in and produced, received the top dramatic prize at the Sundance Film Festival. The film saw the actor teamed with Laura Dern, Peter Krause, and Naomi Watts and traced the crumbling of four characters' friendships and marriages when two of them engage in an affair. Ruffalo's next two roles would be increasingly lighter by comparison. In the Charlie Kaufman-scripted brain twister The Eternal Sunshine of the Spotless Mind, he played a goofy scientist who attempts to erase Jim Carrey's memories of Kate Winslet. He then starred opposite Jennifer Garner in the romantic comedy 13 Going on 30. Three for three with the critics in 2004, Ruffalo's next project of the year was not only met with positive reviews but was a box-office winner as well. In Michael Mann's Collateral, Ruffalo played the lawman trying to track down a menacing hitman played by Tom Cruise as the hired gun terrorizes cabdriver Jamie Foxx. Ruffalo attempted to capture a mass audience with a pair of big-budget romantic comedies in 2005. Sadly, both Just Like Heaven and Rumor Has It... failed to garner large box office, even though Ruffalo was fine in both efforts. The next year, he appeared in Kenneth Lonergan's second directorial feature, Margaret, and he was part of the powerhouse cast for Steven Zaillian's remake All the King's Men, which included Sean Penn, Jude Law, Kate Winslet, and Anthony Hopkins. While All the King's Men, too, failed to gain a solid following -- an especially shocking surprise given the powerhouse cast on display in the film -- the verdict on Margaret had yet to be decided when, in early 2007, Ruffalo appeared onscreen opposite Robert Downey Jr. and Jake Gyllenhaal in director David Fincher's Zodiac.