Brokeback Mountain (left) premieres in the U.S., and Ledger's performance as the tortured, strong-and-silent Ennis Del Mar earns raves. The Los Angeles Times calls the actor "breathtaking," adding that he "brings this film alive by going so deeply into character, you wonder if he'll be able to come back." Director Ang Lee tells PEOPLE that Ledger's performance is reminiscent of "a young [Marlon] Brando."
Brokeback Mountain comes into Oscar night with eight nominations, including his-n-hers nods for Ledger and Williams. (He's up for Best Actor; she's in the running for Best Supporting Actress.) The couple shine on the red carpet (right), but the evening proves to be a disappointment. The movie's stars are shut out of all acting awards, and Crash pulls off an amazing come-from-behind win for Best Picture. Lee does, however, win Best Director.
It seemed Ledger couldn't stop gushing about his home life, calling Williams "the perfect mom" on The Oprah Winfrey Show in 2006. But in October 2007, Ledger and Williams announce their split. Soon after, Ledger is spotted with former supermodel Helena Christensen. But she is quick to shoot down rumors of romance. "It's so annoying," she tells PEOPLE. "I can't even tell you."
Ledger's portrayal of the Joker in The Dark Knight – the sequel to 2005's Batman Begins starring Christian Bale – generates buzz for Ledger. "It's the most fun I've had with a character and probably will ever have," Ledger says. When the film is released after Ledger's death, it shatters box office records and earns him an Oscar nomination and Golden Globe award for best supporting actor.
Ledger is found dead at his Manhattan residence. He was 28. The Oscar-nominated actor is survived by his daughter, Matilda, who inherits his entire estate. On Feb. 6, the NYC medical examiner's office rules that Ledger died of an accidental overdose of prescription drugs. (Click here for all the latest updates on Heath Ledger).
After Ledger's private memorial, Michelle Williams says in a statement, "My heart is broken...I am the mother of the most tender-hearted, high-spirited, beautiful little girl who is the spitting image of her father. All that I can cling to is his presence inside her that reveals itself every day." That same week, PEOPLE reveals heartbreaking details about Ledger's fear of losing Matilda and how his drug use affected his relationship with Williams.
Ledger's family accepts his posthumous Academy Award for Best Supporting Actor in The Dark Knight. "Tonight we are choosing to celebrate and be happy for what he has achieved," his mother Sally Bell, who stood alongside Heath's father Kim Ledger and sister Kate, says while accepting his Oscar. Ledger's daughter Matilda will inherit his Oscar when she turns 18.
BIOGRAPHY (top to bottom): Focus; Steve Granitz/WireImage; Everett Collection; Mark J. Terrill/AP