I Am Heath Ledger will showcase never-before seen home footage of the actor, providing a rare look into his personal life and his passion for film.
"There were always cameras around, a video camera, a polaroid camera or the film camera. That's the only way I think of him," model Christina Cauchi said in the trailer.
The documentary is the latest instalment in director Derik Murray's I Am series, which explores the lives of other iconic figures in film, music and the media.
Murray's other subjects have included Bruce Lee, Evel Knievel and Steve McQueen.
Long-time friends, family members and film colleagues, like Brokeback Mountain director Ang Lee, paid tribute to Ledger in the trailer.
"Even as the supporting actor, he will steal the whole show. That's the power of Heath Ledger," Lee said.
"Before Brokeback Mountain came out it would have been unthinkable to have a romantic tragedy involving two gay cowboys. This is one of the biggest heartthrobs on Earth taking on that character — that's an artist," Australian actor Ben Mendelsohn said.
"He was always a director — acting was just a way to get there," his childhood friend, Trevor DiCarlo, said.
"He wanted fame, and then when he got it, he didn't want it," filmmaker and friend, Matt Amato, said
I Am Heath Ledger will premiere at the Tribeca Film Festival on April 23 and be in cinemas on May 3.
Exhibition honouring life and work of Heath Ledger
The documentary comes ahead of an exhibition set to open in Perth later this year, celebrating Ledger's life and work.
Titled A Life in Pictures, the exhibition will see some of the actor's most prized possessions, including his cameras, skateboards, high school blazer, Academy Award and Golden Globe, go on display at the Art Gallery of Western Australia.
The costume he wore for his penultimate role as the Joker in The Dark Knight and for his ground-breaking role in Brokeback Mountain will also go on display.
His father, Kim Ledger, said despite his son being a private person, he thought he would have supported sharing the items.
"We're celebrating his life as a lovely child who we're terribly, terribly proud of, but also as a foremost Western Australian who made his mark around the world in the film industry," Mr Ledger said.