Now, English actress Sarah Miles - who played Rosy Ryan in the movie - is penning a sequel and Dingle locals are wondering what's next!
Case in point: one day, during a break from filming, Mitchum took his Porsche out for a spin on Kerry’s country roads when he came across a traffic jam - a farmer walking his cattle in the road.
The story goes that the actor impatiently asked the farmer if he could move his animals along faster.
Obviously unimpressed by Mitchum’s fame, the farmer ignored him. A furious Mitchum responded: “Don't you know that I'm Robert Mitchum?" The local said he didn't care if he was Robert Emmet, his animals would move along at their own pace.
Besides messing with the locals, the notorious hard-partying Mitchum, who reportedly wasn’t a big fan of Ireland, spent his time off set cavorting with young women in his Irish guesthouse run by Margaret Sheehy.
In “A Bit of a Fillum,” an RTE documentary about the making of “Ryan’s Daughter,” Sheehy revealed that Mitchum had many young women ferried in to amuse him during his stay in the rainy, rural area. Whenever Mitchum’s wife threatened to fly into town, local auctioneer John Moore would whisk the mistresses off to Shannon.
"Mom, you're running a brothel," Margaret Sheehy's children would say to her.
Co-star Sarah Miles, though married to the film’s writer, was reportedly "very fond" of Mitchum, and according to Sheehy, on many nights "she'd breeze in upstairs to him, and I'd just close my eyes to those things.”
Mitchum ended up inviting Sheehy to the London premiere of “Ryan’s Daughter,” but Sheehy declined.
De Mordha, who knows Sarah Miles well, thinks a sequel to the Irish film will be met with a warm welcome in Ireland.
If Miles rebuilds the fictitious Irish village of Killary, and brings the world of “Ryan’s Daughter” back to life, de Mordha says: "It would turn back the clock to that glamorous time – the whole of 1969, a period that is still known as The Year of the Film."
"It wasn't quite a one-horse town, but it certainly was a sleepy place before ‘Ryan's Daughter’" de Mordha said.
"After it, Dingle was never the same – it only got better and bigger. Even today – and almost every day – I meet tourists who come to this part of Kerry looking for the ‘Ryan's Daughter’ experience."
The film boosted Dingle's economy to the tune of $1.8 million in 1969. The filmmakers hired locals as extras, caterers and drivers, and paid them up to three times their normal salaries.
"Some of the people who live here now just came to west Kerry looking for work because the film was shooting here," de Mordha says.