In 2023, Neill disclosed he had been diagnosed with angioimmunoblastic T-cell lymphoma, a rare type of non-Hodgkin lymphoma. Neill died on Monday in Sydney, according to a statement posted to the actor's social media page.
His death was "sudden and unexpected", the statement said, adding he "remained cancer free" when he died. A cause of death wasn't specified.
"Sam was surrounded by family and passed with the dignity that has characterised his whole life," his family wrote.
Neil was one of a host of actors and directors who achieved international fame after an explosion of Australian films that began in the late 1970s, a list that includes Paul Hogan, Mel Gibson, Geoffrey Rush, Russell Crowe, Jane Campion, Peter Weir and Gillian Armstrong.
His range was remarkable, playing opposite Helena Bonham Carter in the Alan Ayckbourn comedy Sweet Revenge to chopping off Hunter's finger in The Piano to poking his own eyes out in the sci-fi horror Event Horizon.
In Omen III: The Final Conflict, he played Damien the Antichrist and he also played Cardinal Thomas Wolsey in The Tudors.
The actor first came to the attention of international audiences in Armstrong's 1979 film My Brilliant Career, which also introduced Judy Davis. He later appeared in Phillip Noyce's Dead Calm, a classy thriller set at sea and co-starring the then-relatively unknown Nicole Kidman.
Neill twice co-starred with Meryl Streep, in Australian director Fred Schepisi's Plenty and — again for Schepisi — in A Cry in the Dark, a film about the sensationalised aftermath of a dingo killing a baby in the Australian Outback.
He earned an Emmy nomination for his performance in the title role of the 1998 mini-series Merlin and another as narrator of 2017's Wild New Zealand.
But perhaps he achieved his highest level of fame in Jurassic Park playing paleontologist Alan Grant, who is summoned to an island off Costa Rica where a theme park has been built to house herds of cloned dinosaurs. He co-starred alongside Laura Dern, Jeff Goldblum and Richard Attenborough.
His character was thoughtful and reasonable, a scientist who warned the mastermind of the theme park before the chaos: "Dinosaurs and man, two species separated by 65 million years of evolution have just been suddenly thrown back into the mix together. How can we possibly have the slightest idea what to expect?"
Grant survived the harrowing events when the creatures get loose, but didn't return for The Lost World: Jurassic Park II in 1997. He came back for the third episode in 2001 and Jurassic World: Dominion in 2022.
"It's probably a little late to learn these things," he told the Daily New of New York in 2001, "but I finally feel I've worked out how to be an action hero. I'm happier with Grant this time. He's gnarly and grizzled, but he looks like he knows what he's doing."
Born in 1947 in Northern Ireland, Neill emigrated to New Zealand at the age of seven. His family settled in Dunedin on the South Island and he was sent to boarding school in Christchurch.
After college, he took the lead in Sleeping Dogs in 1977, the first feature made in New Zealand in more than a decade.
Neill's other film roles included playing a Soviet submarine officer who memorably dreams of a home in Montana in The Hunt for Red October and an investigator in director John Carpenter's In the Mouth of Madness.
On the small screen, Neill played the malign Chester Campbell in TV's Peaky Blinders and Thomas Jefferson in the four-hour CBS miniseries, Sally Hemings: An American Tragedy.
On Apple TV+, he was on Invasion, playing Oklahoma Sheriff John Bell Tyson, a man late in his career searching for his purpose. In 2024 he starred opposite Annette Bening in the Peacock series Apples Never Fall.
Neill was also a vintner and under his Two Paddocks brand, he produced pinot noir and riesling wines from his winery in the Central Otago region of New Zealand's South Island.
On social media, he often posted images of his farm animals, many of them affectionately named after celebrities and friends, like Laura Dern the chicken, Kylie Minogue the duck and Helena Bonham Carter the cow.
His memoir Did I Ever Tell You This? came out in March 2023 and he was awarded a knighthood in recognition of his "outstanding contribution to film", a title approved by the late Queen Elizabeth II.
"I can't pretend that the last year hasn't had its dark moments," Neill told The Guardian in 2023, referring to his cancer diagnosis and treatment.
"But those dark moments throw the light into sharp relief, you know, and have made me grateful for every day and immensely grateful for all my friends."
He is survived by four children and eight grandchildren.
