Jul. 28—As a Boston native, Matt Damon has heard his share of exaggerated accents.

So, when he took on the role of an Oklahoma oilfield worker named Bill Baker in the film “Stillwater,” the three-time Oscar-nominated actor took care not to overdo the drawl.

“I get that up in Boston, too: When people come and try to do it from out of town, they overcook it a little bit. So, I really put a lot of time into it,” Damon said. “It was all about just trying to be as accurate as possible, because the movie, it goes to all of these kind of different, unique places. It doesn’t track like a normal movie, so you really have to be with Bill. You have to go for that ride with that character. So, if you don’t believe in him, then we’re sunk.”

At 50, Damon is earning widespread praise for his performance as a roughneck from Stillwater who travels to Marseille, France, to visit his daughter, Allison (Oscar nominee Abigail Breslin), in prison. A former Oklahoma State University exchange student convicted of murdering her girlfriend, Allison has always maintained her innocence, and when a new lead is dismissed by her attorney, Bill sets out to investigate on his own.

Hampered by his lack of knowledge of the local language, customs and legal system, Bill finds an unlikely ally in Virginie (Camille Cottin) a French theater actress and single mom to a lively 8-year-old daughter, Maya (Lilou Siauvaud), who takes an immediate liking to the taciturn American.

“We wanted to ... try to show a real Oklahoman in this man. With all his flaws, I love that character,” Damon said in a phone interview. “I think it’s a beautiful movie, and it’s the kind of movie that’s not getting made anymore.” Made in Oklahoma

The latest movie from Academy Award-winning writerdirector Tom McCarthy (the fact-based journalism drama “Spotlight”), “Stillwater” filmed in 2019 in Marseille as well as in and across Oklahoma City, Stillwater, Arcadia and Coyle.

Producer Jonathan King said the Oklahoma Film Enhancement Rebate helped make lensing in Oklahoma possible.

“The goal, the sort of dream of any filmmaker or producer when you’re making a movie that’s about real people in a real place is to make the movie there. And so that was always our starting point: We want to shoot Marseille for Marseille; we want to shoot Oklahoma for Oklahoma. But it has to be practical,” King said at a 2019 OKC event.

“You need facilities, locations, crew, equipment to properly fit all of that stuff; fortunately, Oklahoma had all of that. Then, for the companies that are financing the movie, it has to be financially attractive. And the incentive program here — so, thank you to the state of Oklahoma — really, really was helpful in us choosing to come here.”

Although “Stillwater” marked his first time to work in Oklahoma, it wasn’t Damon’s first visit to the Sooner State.

“Every ‘Bourne’ movie, we did a premiere in Oklahoma. We found with those movies, we’d like to take them around the country and show people. And Oklahoma City was one of our really fun destinations. We always had a great time there. Frank Marshall, our producer, always organized that because he has ties to Oklahoma City,” Damon recalled. “And I’ve driven across America probably 12 times, trying to get out to either L.A. or to get back to Boston. So, I’ve been through Oklahoma a whole bunch.”

Accurate portrayal

To ensure that his “Stillwater” protagonist was an authentic, fully developed character and not a stereotype or caricature, Damon returned to Oklahoma with McCarthy to spend time with real roughnecks.

“They were understandably wary at first. They were like, ‘Well, what are you doing making a movie about roughnecks? What are you trying to say about us?’ I think it was getting to know Tom and getting to know me and and seeing the script and understanding what the story was, they realized, ‘Oh, this movie has a lot of empathy and compassion for Bill,’ and we just want to get this roughneck right,” Damon said.

“Once they realized that our intentions were pure, they could not have been more helpful. I’m so grateful for all the help. They really made this performance what it is.”

The Oscar-winning co-writer of “Good Will Hunting” said Kenny Baker of OKC’s Cactus Drilling became a go-to resource on the film. He got the call, for instance, when Damon and McCarthy couldn’t settle on the bluecollar Okie way to pronounce “theater.” (The actor noted that Baker backed his claim that “the-A-ter” would be the roughneck way to say it.)

“We took a lot of pictures, and Kenny had us over to meet his whole family and have a barbecue in his backyard,” Damon recalled. “I changed my body a little bit to affect their body type a little more, because I noticed there’s a body type for those guys. If you go out on those rigs and try to lift some of that equipment, you gotta be real strong — and those guys are real strong. They’re like country strong. They don’t look like they’ve got Brad Pitt abs: the young guys do, but Kenny and the guys my age, we usually have a little belly. But they’re incredibly strong guys, so all those details — the walk and the physicality of it — it really came from my time with them.”

From the way his character props his sunglasses on his cap to the way he moves in heavy work boots and pants, Damon said his time in Oklahoma helped him get the details right.

“A performance is really just all these details in aggregate,” he said. “If I’m in the audience in a movie, if I don’t believe a performance, I might not be able to actually tell you why. It’s just a feeling, and what I think that feeling is, it’s all those little signals, all those little things like the sunglasses on the hat. ... If you miss enough of those, people just kind of don’t buy your act. So the more detailed you are, the more believable you’re going to be.”

Thrilling drama

Although “Stillwater” is considered a thriller, Damon said the film also is a family drama. He isn’t playing the usual Hollywood version of an American hero like Jason Bourne.

“It feels like it has that typical setup, but then that’s basically all it shares with those movies. The rest of it, we play it very real. The guy doesn’t have the skills. The fun of those Liam Neeson movies is you know he has all the skills, or the Jason Bourne movies, for that matter, same thing: He’s got all of the skills that he’s going to need to win the day,” Damon said.

“But Bill Baker, he doesn’t speak the language, he’s not familiar with the culture. He’s got everything kind of stacked against him, but he’s got this huge impulse to help in any way he can because he wants to repair the damage he’s done to this relationship with his daughter.”

After a long delay due to the COVID-19 pandemic, “Stillwater” opens in theaters July 30, after a world premiere at the prestigious Cannes Film Festival in France, where it received a five-minute standing ovation. The film has earned a slew of positive reviews and comments from preview screenings.

“I got choked up at Cannes when we did the world premiere at that festival. We waited for so long to bring it out, but then also just the feeling of being back in the movie theater again with people, I just felt so grateful. This last year and a half, it’s been hard on everybody, and again. ... I didn’t see that coming at all; that moment kind of snuck up on me, but I really felt grateful to be able to be in a movie theater again, showing the work that we did,” Damon said.

“And I’m really just unbelievably relieved that people from Oklahoma seem to like it.”