Thornton was born and raised in Alice Springs. His mother, Freda Glynn, co-founded and was the first Director of the Central Australian Aboriginal Media Association (CAAMA), and was the Director of Imparja Television for its first ten years. For a time she was the only female chair of a television network in the world. In 1993 she, together with Philip Batty, won the $50,000 international prize in communications, the McLuhan Teleglobe Canada Award.
At 13, Thornton was sent to school in Australia's only monastic town, New Norcia, Western Australia, although he later declared he became angry with Christianity and did not consider himself religious.
Thornton is married to screen writer and film director, Beck Cole, and they live in Alice Springs. "She's the boss," he laughs. "I ask 'Can I shoot your film babe?' and she says, "Well, if you do the washing up and mow the lawn.' She's bulletproof and much stronger than me." Together they have a daughter, Luka May, while Thornton also has another daughter, Rona, and a son, Dylan, from a previous relationship.
He has two brothers, Scott Thornton, is an actor who played the role of Gonzo in Samson and Delilah (2009 film), and Rob Thornton who is an indigenous liaison officer in Cairns Base Hospital, Queensland.
He graduated in cinematography from the Australian Film, Television and Radio School. Thornton began his career making short films and has achieved success with them at film festivals around the world, including Payback at the Telluride Film Festival and Green Bush and Nana at the Berlin International Film Festival. He describes his decision to become a filmmaker in an interview in 2007:
Where I grew up in Alice I was a DJ for a radio station (CAAMA). The station began a film unit and so I watched people pack cameras and equipment into cars and take off to make films. I was alone at the radio station and I thought that I really wanted to go with them. That’s how it started, I made a film called Green Bush which is basically about that time. Eventually I went to AFTRS in Sydney and got really involved as a Director of Photography. I’ve been in the business for 9 years now.
Awards and nominations
- 2007: Melbourne International Film Festival. Melbourne Airport Award for Emerging Talent for Nana
- 2007: Inside Film Awards (or IF Awards). Best Short Film for Nana
- 2008: Berlin International Film Festival. Best Short Film for Nana
- 2009: Cannes Film Festival. Caméra d'Or for Samson and Delilah
- 2009: Australian Writers' Guild Award: Feature Film Screenplay (Original) for Samson and Delilah
- 2009: Deadly Awards: Outstanding Achievement in Film for Samson and Delilah
- 2009: IF Awards: Best Director, Best Script, and Best Music for Samson and Delilah, and Best Short Film Director for Nana
- 2009: AFI Awards: Best Director and Best Original Screenplay for Samson and Delilah
- 2009: The Dinosaur Design IF Award for Best Music for Samson and Delilah
- 2009: The National Film and Sound Archive IF Award for Best Direction for Samson and Delilah
- 2009: Northern Territorian of the Year.
- From Sand to Celluloid – Payback (1996 Blackfella Films, short film, also writer)
- Willigan’s Fitzroy (2000, documentary, also writer)
- Mimi (2002 Blackfella Films, short film, also director, starring Aaron Pedersen and Sophie Lee)
- Green Bush (2005, short film, also writer, starring David Page)
- The Old Man and the Inland Sea (2005, documentary, also writer)
- Burning Daylight (2007, documentary)
- Dark Science (2007, documentary, co-director)
- Nana (2007, short film)
- Samson and Delilah (2009)
- Art + Soul (2010)
- The Darkside (2013)
- Words With Gods (2014)
- Marn Grook: An Aboriginal Perspective on Australian Rules Football (1997, documentary)
- Radiance (1998, feature film, directed by Rachel Perkins)
- Buried Country (2000, documentary, directed by Andy Nehl, based on the book by Clinton Walker)
- Ngangkari Way (2001, documentary, directed by Erica Glynn)
- Flat (2001, short film, directed by Beck Cole)
- Mimi (2001, short film, directed by Warwick Thornton)
- Kurtal: Snake Spirit (2002, documentary, co-cinematographer)
- Queen of Hearts (2003, directed by Danielle MacLean)
- Wirriya: Small Boy (2004, documentary, co-cinematographer, directed by Beck Cole)
- Five Seasons (2005, documentary, directed by Steven McGregor)
- The Lore of Love (2005, documentary, directed by Beck Cole)
- My Brother Vinnie (2006, documentary, directed by Steven McGregor)
- Plains Empty (2006, short film, directed by Beck Cole)
- Green Bush (2006, short film, directed by Warwick Thornton)
- First Australians (2006, television series, directed by Beck Cole & Rachel Perkins)
- Samson & Delilah ( 2009, Feature Film, directed by Warwick Thornton)
- Here I Am ( 2011, Feature Film, directed by Beck Cole)
- The Sapphires (2012, Feature Film, directed by Wayne Blair)
- Canada Council of the Arts
- Smith, M. "Thornton nails his latest work", The Koori Mail, 21 September 2011, p. 84.
-  "Erica Glynn." Deadly Vibe Issue 78 September 2003
- Australian Screen
- Melbourne Airport Emerging Talent Award
- "Aboriginal director honoured at Cannes", ABC News, 25 May 2009