Ledger was raised in Perth, Austl. He began acting in school productions in junior high and moved to Sydney at age 17 to pursue a career in performance. His first roles were on television, and in 1997 he appeared in the Australian soap opera Home and Away and in the mythic adventure series Roar. Ledger proceeded to take a number of minor roles in films, including the black comedy Two Hands (1999). His first Hollywood movie, the teen romance 10 Things I Hate About You (1999), won him great attention.

Ledger resisted being typecast as a teen heartthrob and developed a reputation for taking divergent character roles. In The Patriot (2000) he starred opposite Mel Gibson (Gibson, Mel) as an American Revolutionary War soldier, and in Monster's Ball (2001) he portrayed a young corrections officer who questions old family prejudices. In 2005 Ledger appeared as pioneering skateboarder Skip Engblom in Lords of Dogtown and as the legendary title character in the comedy Casanova. Ledger drew further praise as a heroin addict in Candy (2006). His sympathetic turn as the taciturn and tormented cowboy Ennis Del Mar in director Ang Lee (Lee, Ang)'s Brokeback Mountain (2005) won him Academy Award and Golden Globe nominations for best actor. The film caused a media sensation because of its frank and sympathetic portrayal of the clandestine gay romance between Ledger's character and another cowboy, played by Jake Gyllenhaal. Ledger then contributed his impressionistic rendering of musician Bob Dylan (Dylan, Bob) to the ensemble cast of I'm Not There (2007).