Cillian Murphy came away with his first Oscar for portraying the man who created the atomic bomb in Christopher Nolan’s blockbuster biopic “Oppenheimer.” The film was crowned best picture and Nolan was named best director.

A first-time nominee, Murphy won best actor for his stellar role as J. Robert Oppenheimer. The film tells the story of how Oppenheimer and his peers at Los Alamos would test the bomb on July 16, 1945, not knowing what was going to happen — and the ensuing fallout.

Murphy bested Colman Domingo for “Rustin,” Bradley Cooper for “Maestro,” Paul Giamatti for “The Holdovers,” and Jeffrey Wright for “American Fiction.”

The Irish actor, though a regular presence in Nolan films going back almost two decades, had always been a supporting player. This time, Nolan wanted him to lead.

“He’s so understated and self-deprecating and, in his very English manner, just said, ‘Listen, I’ve written this script, it’s about Oppenheimer. I’d like you to be my Oppenheimer,’” Murphy, 47, told The Associated Press last year. “It was a great day.”

For Murphy, he knows there are some movies he’s right for and some that he is not.

“I have always said publicly and privately, to Chris, that if I’m available and you want me to be in a movie, I’m there. I don’t really care about the size of the part,” he said last year. “But deep down, secretly, I was desperate to play a lead for him.”

Murphy came into the Academy Awards a strong contender after picking up trophies at the Golden Globes, SAG Awards and BAFTA Film Awards.