Friends and admirers of Heath Ledger are mourning his loss and recalling his achievements in a film career cut short by his death Tuesday at age 28. Mike O'Sullivan looks back on his transition from teen actor to talented star.

Makeshift memorial for Heath Ledger in front of his apartment building in New York, 23 Jan 2008

Colleagues in Hollywood expressed shock at Ledger's death, and admiration for his skill as an actor. Geoffrey Rush, who starred with Ledger in the films Ned Kelly and Candy, called him a sensitive and daring performer. Mel Gibson, who selected the young star for the film The Patriot, called the death tragic. Gibson said in a written statement, "I had such great hope for him." Ang Lee, who directed Ledger in Brokeback Mountain, called the young star a joy to work with. The actor John Travolta said Ledger's talent touched him.

Ledger was born in Perth in Western Australia in 1979. He discovered acting through a drama class in high school. After work in Australian films and television series, he moved to Los Angeles and starred in the 1999 teen comedy 10 Things I Hate About You.

Then came a role in a big production, The Patriot, a tale of the American Revolution. In the film, Ledger tries to convince his reluctant father, played by Mel Gibson, to join the fight again the British.

In 2001, Ledger starred in a light-hearted action film called A Knight's Tale. He also gained notice for a role in Monster's Ball, a story about race relations in the American South. It was first of the intense, serious roles that he became known for.

In 2003, he played the title role in Ned Kelly, about a legendary Australian outlaw. There were also lighter roles. He played opposite Matt Damon in the fantasy adventure The Brothers Grimm, and had a starring role in Lords of Dogtown, which looked at the world of California surfers.

Ledger played opposite Jake Gyllenhaal in the critically acclaimed Brokeback Mountain, a 2005 film about two cowboys who fall in love. Both actors earned Oscar nominations for their roles as men tormented by their mutual attraction.

In 2006, Ledger played a poet who was addicted to heroin in the Australian drama Candy.

More recently, he was one of six performers who portrayed singer Bob Dylan at different stages of his career in I'm Not There.

In what some critics say may be Ledger's best and darkest role, he plays the fiendish Joker in the upcoming Batman film The Dark Knight. The picture is scheduled for release in July. Ledger adds an edge to the character made famous by Jack Nicholson, who challenges Batman and local officials in the fictional Gotham City.

As coworkers and fans recalled Heath Ledger's talent, the actor's father, Kim, remembered his son as down-to-earth, generous and kindhearted.

Ledger has a two-year-old daughter, Matilda, from his relationship with actress Michelle Williams, who played his wife in Brokeback Mountain.  The couple broke up last September.