He’s worked with the Coen Brothers, Paul Thomas Anderson, and Denis Villeneuve, but Brolin tells IndieWire that he finds unique challenges in Thanos and Cable as well.

In 1989, Josh Brolin starred in the ABC western series “The Young Riders.” Then recently married with a kid, the 21-year-old actor began attending AA meetings while shooting on location in Tucson. There he met fireman Danny Martin, who would become his close friend of three decades.

“He introduced me to an incredible community [of firefighters] that I am still very close with,” said Brolin. “I just spent a lot of time with firefighters since my early 20s. I love the ribbing, I love that you have to man up. They challenge you and if you can’t hang you won’t hang, they won’t let you hang.”

So Brolin was extremely skeptical when director Joseph Kosinski (“Tron: Legacy”) approached him with a script about the famed Granite Mountain Hotshots — the heroic Prescott, Ariz. fire crew that battled the Yarnell Hill fire in 2013 and tragically lost 19 members (many of whom Martin knew personally).

In playing Granite Mountain Hotshot leader Eric Marshin in “Only the Brave,” Brolin knew the importance of getting the story right. He questioned if Kosinski, best known for his work with CGI, was the right person to tell the story.

Richard Foreman, Jr./LIONSGATE

“I’ve gotten very spoiled working with directors at the top of their game and he was someone who was technically proficient, but to me hadn’t done an emotional story,” said Brolin, whose career includes films with the Coen Brothers, Paul Thomas Anderson and Denis Villeneuve. “There will be a lot of those types of guys that will be like, ‘This is my passion project, man, and I’m going to be on your eyes, because it’s all about your eyes tell a story,’ and you’re just like, ‘Oh fuck, get me out of here.'”

With Kosinski, Brolin took the attitude of an Arizona firefighter: Prove it. The director’s straightforward, no B.S. persistence eventually won Brolin over.

“I believed him, and I was like, ‘If you want to partner up with this, I don’t want you to be one of those directors who says you’re going to be in the middle of it and then suddenly you are in your cush car with a cashmere sweater on — I want you to be out there with us,'” said Brolin. “And he was, very much. He was as much one of the guys as anyone.”

What Brolin loved about his firefighter friends — across all the varied personalities, some total misfits — was a familial bond rooted in knowing that each member could be counted on, both in fighting fires and in life. He took the same “man up” attitude toward the actors who portrayed his onscreen crew, including Miles Teller, James Badge Dale, and Taylor Kitsch. Brolin led a pre-shoot regimen that mirrored the Hotshots’ mountain training, one that went well beyond the fitness routines most actors know.

Richard Foreman, Jr/LIONSGATE

Brolin told his Hotshot co-stars: “‘You have a skill, which is acting, but I don’t you want to live as actors. There’s too much entitlement. So we’ll live as much as possible as these guys lived during this process. So when you carry a 45-pound pack after a month, you aren’t going to ask the prop guy to put foam in your backpack. If anything, I want people filling their buddies’ packs with more rocks.’ I think that [mentality] was established in the beginning.”

Brolin says he did this as much for himself: He found the prospect of playing Marsh terrifying. Brolin made sure to surround himself with those who knew the Granite Mountain crew, including Marsh’s real-life mentor Duane Steinbrink, who Jeff Bridges played in the film.

“Josh took on this part in such a way that many actors wouldn’t,” said Bridges. “You want to do a certain amount of training, sure, but he took it to the nth degree. He trained with all the other actors, in their parts, like it was a giant improv. He was the head of the hotshots, he took that on and the other actors appreciated that. It made their job easier.”

Richard Foreman, Jr./LIONSGATE

Despite all the physical training “Only the Brave” demanded, Brolin said it didn’t prepare him for his recent action films. He’s villain Thanos in the next two “Avengers” movies and Cable in “Deadpool 2,” which he just wrapped with stunt coordinator-turned-director David Leitch (“John Wick,” “Atomic Blonde”).

“It’s like for [‘Only the Brave’] I needed to be in great interior shape, where as or ‘Deadpool’ it was more exterior,” said Brolin. “Every stunt man thinks I’m a stunt man, and I have to remind them that I’m actor. Dude, it’s both the best [doing action scenes with Leitch] and it’s awful. I’m almost 50 and I’m feeling it. I’m feeling it in my knee, my shoulder has to get fixed now, I got to get the hernia operation. I’m thinking if I’m doing four of these movies and I’m 60 doing ‘Deadpool 9,’ fuck this, I’m screwed, it’s going to be Cable with a walker.”

Brolin says he made a concerted effort to branch into tentpole films after “Only the Brave.” He liked the idea of playing the brilliant Thanos who takes on the Avengers — but the irreverent tone of “Deadpool” meant he struggled to find his place in a crew of comedic actors.

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“There’s something very attractive to me about doing these bigger movies, and it’s not about the money,” said Brolin, who said he made more money on “Only the Brave” than one the two tentpoles. “Then there’s the aspect I’m not [attracted to]. I won’t talk about which movie, but one of these tentpole movies was the least kind of communal experience I’d had. Ok, it’s a machine and it’s much bigger than anything I had ever experienced and people are coming and going. It’s just a different experience from Granite Mountain, where you’re just there all the time — you are basically living with these guys day in and day out. And I really enjoy that and so as an experience, as a selfish experience, I prefer that.”

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