Until he was 13, Warwick Thornton was a “lost kid” who was “drinking, smoking, thieving and fighting”. The future film director and writer of Samson & Delilah spent three years skipping school and roaming the streets of Alice Springs where he was born, some 400 kilometres south of his people’s country, the Kaytej nation. So his mother did something radical.

Thornton, now 38 and about to premiere his first feature film Samson & Delilah – an extraordinary tough-love tale of two Aboriginal teenagers blighted by poverty, violence and petrol sniffing – was masking a fear of authority. “I hated school, I didn’t like teachers; I was afraid of teachers,” he admits.

He never knew his father. Thornton’s mother, Central Australian Aboriginal TV and radio pioneer Freda Glynn – who as a child during Japan’s advances on the Pacific in World War II had been evacuated from Alice Springs to a church missionary camp in the Blue Mountains – thought distance might fix her wayward boy.

She packed him up, sending him off to live and study at Australia’s only monastic town, New Norcia, in Western Australia in 1983. Thornton arrived at what was then known as Salvado College, established in 1846 by a Spanish missionary as part of a Benedictine monastery 132 kilometres and two hours’ drive north of Perth.

Bishop Rosendo Salvado’s original missions had been to “civilise” Aboriginal children – with a “progressive” interest in indigenous culture said to be rare for his day – and to make his Christian village largely self-sufficient based on agriculture.

The 13-year-old Thornton found himself picking olives with a lot of other “country black fella” kids and facing the rigour of school and religious observance. “Somehow I went from street kid to going to church twice a day,” says the tall, broad-shouldered, bearded director 25 years on. “It was like lockdown, you were in the middle of nowhere.” Yet he was surprised how the monastery affected him. “I actually found it really uplifting because I found structure and I found self respect.”

And he began to find his voice, first as a DJ at the radio station run by his mother and others when he returned to Alice Springs at 15; Freda was a co-founder of broadcast network Central Australian Aboriginal Media Association. On his program, he would play songs specially requested by prison inmates.

Growing bored with that gig, Thornton leapt into cinematography when the association launched a film unit, which eventually led him to study at Sydney’s Australian Film, Television and Radio School, during which he began to make a succession of short films about his world, from traditional Aboriginal law to life in remote communities. He graduated in 1997.

Thornton is now married to film writer and director Beck Cole, a Warramungu woman he met 10 years ago, and they live in Alice Springs. “She’s the boss,” he laughs. “I ask ‘Can I shoot your film darling?’ and she says, ‘Well, if you do the washing up and mow the lawn.’ She’s bullet-proof, and much stronger than me.” The couple’s collaborations include the SBS series First Australians, and they have a daughter, Luka, 5, while Thornton also has another daughter, Rona, 13, and a son, Dylan, 16, from a previous relationship.

Samson & Delilah producer Kath Shelper says when she met Thornton in 2004 and worked on his short film Green Bush he was “gruff and a bit dismissive of producers” – Thornton admits now he was then still “insecure” – though Aboriginal art curator Hetti Perkins, with whom Thornton is currently making the three-part documentary Art + Soul, says that like Shelper she’s found a creative and thoughtful ally in Thornton.

“He’s the kind of person who will let you talk for hours, which means he’s listening,” says Perkins. “I find him quite fearless, too, to make courageous choices to get beyond the skin of things. And funny – a healthy dose of humour runs through his work, even though the things he’s dealing with are serious.”

Thornton’s first feature is strengthened by its long silences and reliance on action, aided by a soundtrack of Aboriginal rock, the country music of African-American singer Charley Pride – a big favourite of Aboriginal inmates, says Thornton – and romantic Mexican numbers penned by Ana Gabriel.

Set in an unnamed remote Aboriginal community, what little is spoken in Samson & Delilah is mostly in the Central Australian language of Warlpiri. First-time actor Rowan McNamara, who plays Samson, is from the Eastern Arrente people, and Marissa Gibson, who plays Delilah and has acted in small parts and as an extra in film and TV roles, is from Alice Springs. Both are now 16 but were 14 when the feature was made.

Delilah’s days and nights are composed of caring alone for her elderly, ailing Nana, played by the delightful Mitjili Gibson, who in real life speaks several Aboriginal languages but little English. The missionary influence permeates the movie, such as when Delilah discovers her Nana has died – she hacks her own hair short as a traditional Warlpiri woman’s way of mourning and eschewing vanity, and as she cuts, she sings Little Baby Jesus.

When Thornton decided to name the film Samson & Delilah, he did not know the details of the original biblical story; he liked the names because they had a Romeo-and-Juliet-ring to them, and he’d known many Aboriginal kids named Samson and Delilah because the missionary influence on indigenous communities meant children were often given biblical names.

One day, however, he picked up a Little Golden Book version of the biblical story, and discovered: “Oh my God, she cuts his hair!” Thornton had already written the Aboriginal Delilah’s hair cutting into his script, but having read the biblical tale of betrayal in which Samson fears cutting his hair will zap his strength, was inspired to have his own Aboriginal Samson cut his hair when the boy misunderstands that only indigenous women should mourn that way.

When Samson and Delilah are forced from their community to live on the streets of Alice Springs, they meet a homeless Aboriginal man, Gonzo, played to great comic effect by Scott Thornton. The inspired acting is made poignant by the fact the actor – the director’s brother – had to attempt alcohol rehab four times before he could film the role, and since the film wrapped has slipped back into his addictions.

“I always tear up when I see my brother up there sober playing a drunk,” says the director. Gonzo, dirty and gruff with missing teeth and about to be housed by Christian missionaries, breaks into Tom Waits’s Jesus Gonna Be Here.

Warwick Thornton says it’s possible to believe in God, Jesus, and Aboriginal dreamtime figures such as the rainbow serpent all at the same time. “Absolutely, it fits perfectly,” he says. “A lot of the bible is moralistically written, ‘Don’t do this’ or the Ten Commandments, how Jesus went up to the mountain and fed everybody, all that kind of concept.

“A lot of dreamtime stories run on the same basis of morals – if you do this, you’ll get in trouble, so don’t do it; the kangaroo got its tale through a spear because it was mucking around with the other kangaroo, you know, very similar to the Bible in a sense.”

Does Thornton believe in God as the monks taught him? “Look, I believe in good and evil and I reckon there’s something else out there. You know, I reckon there’s a higher concept.

“Whether his name’s God and he’s got a son named Jesus I don’t know. But I believe in the Dreaming as well, you know? I’m quite happy to believe in the rainbow serpent.”