George MacKay delivers a star-making performance in “1917.” After making his film debut at age 10 in the 2003 live-action “Peter Pan,” he played occasional film and TV roles and realized at age 19 “acting is what I wanted to do.” Since then, he’s appeared in an earlier WWI saga, “Private Peaceful,” and played Viggo Mortensen’s rebellious son in “Captain Fantastic” —  and he has three more films coming up.

When you started acting, did you have any role models?

I liked performances that are commanding, brave and big, like John Leguizamo in Baz Luhrmann’s “Romeo + Juliet,” and I loved everyone in “Gladiator.” As I got older, I would hear actors talking about “smaller is better, less is more.” I understood that when I saw Al Pacino in the“Godfather” movies. He does nothing, but he does everything; it’s all going on with him.

What was your first reaction on reading the “1917” script?

It was 54 takes. That said, there were at least 20 rehearsals before that. Everything was rehearse, rehearse, rehearse, so you don’t want to exhaust it, but you need to know what’s happening. Probably the toughest part for everyone was how to meter yourself, how to keep stamina. You have to go with each take as if it’s the first and as if it’s the last.

Was the scope of “1917” overwhelming?

The process of making it was so unlike anything else. Everyone was starting together on the same day, everyone took the first step together. So there were no insecurities about joining a project in progress. Everyone was informing each other all the time. We had to work out the camera moves; in general, what [my character] Schofield is seeing is what the camera’s seeing. That was quite integral to the characterization. The way Schofield got through the war is to concentrate on what’s in front of him and not bring in anything else, like memories of home, or look around and see too many dead bodies, because he would get overwhelmed.

The 10 Oscar nominations must be gratifying.

Yes, and the best picture nomination is especially wonderful because it involves everybody. So many people who worked on this film don’t get enough shout-outs for the work they do. The art department, the transport department, greens department, costume designers Jacqueline Durran and David Crossman — the brilliance of all these people is that you don’t notice their work. In a way, you don’t want to tell people too much, to take away the magic. But they were all so brilliant.

What’s upcoming?

“The True History of the Kelly Gang.” I’m so proud of that film. Justin Kurzel made it with such integrity. I think he’s visionary. It’s a complete twist on the story of (Australian outlaw legend) Ned Kelly, based on a Peter Carey novel. It’s about how you appropriate history to mean what you want. It’s a beautiful, brutal film, and unlike any other film I’ve seen.