Heath Andrew Ledger was an Australian actor. After playing roles in several Australian television and film productions during the 1990s, he moved to the United States in 1998 to further develop his film career. His work consisted of 20 films in a variety of genres, including 10 Things I Hate About You (1999), The Patriot (2000), A Knight's Tale (2001), Monster's Ball (2001), Casanova (2005), Lords of Dogtown (2005), Brokeback Mountain (2005), Candy (2006), I'm Not There (2007), The Dark Knight (2008), and The Imaginarium of Doctor Parnassus (2009), the latter two of which were posthumously released. He also produced and directed music videos and aspired to be a film director.

Ledger was born on 4 April 1979 in Perth, Western Australia, to Sally Ramshaw, a French teacher, and Kim Ledger, a racing car driver and mining engineer whose family established and owned the Ledger Engineering Foundry. The Sir Frank Ledger Charitable Trust is named after his great-grandfather Frank Ledger. He had English, Irish, and Scottish ancestry. Ledger attended Mary's Mount Primary School in Gooseberry Hill and later Guildford Grammar School, where he had his first acting experiences, starring in a school production as Peter Pan at age ten. His parents separated when he was ten and divorced when he was eleven. Ledger's older sister Kate, an actress and later a publicist, to whom he was very close, inspired his acting on stage; and his love of Gene Kelly inspired his successful choreography, leading to Guildford Grammar's 60-member team's "first all-boy victory" at the Rock Eisteddfod Challenge. Ledger's two half-sisters are Ashleigh Bell (b. 1990), his mother's daughter with her second husband Roger Bell; and Olivia Ledger (b. 1996), his father's daughter with his second wife Emma Brown.

Ledger was an avid chess player, and had participated in tournaments when he was young. As an adult, he often played with other chess enthusiasts at Washington Square Park in Manhattan. He was a fan of West Coast Eagles, an Australian rules football team that competes in the Australian Football League (AFL) and is based in his hometown of Perth.

At around 3 p.m. Eastern Standard Time on Tuesday, 22 January 2008, Ledger was found unconscious in his bed by his housekeeper, Teresa Solomon, and his massage therapist, Diana Wolozin, in his loft at 421 Broome Street in the SoHo neighbourhood of Manhattan.