Cillian Murphy earned his first Academy Award for his portrayal in “Oppenheimer” of the physicist who led the United States’ development of the atomic bomb during World War Two.

The win caps a successful awards season for the 47-year-old Irish actor, who also picked up a Golden Globe, a BAFTA and a Screen Actors Guild award for his performance. It was his first Oscar nomination.

Murphy, who lives in Ireland and keeps a low profile in Hollywood, had his biggest role to date playing a tortured, morally ambiguous Oppenheimer. He is also known for leading roles in films including “28 Days Later” and crime show “Peaky Blinders,” and for appearances in other Christopher Nolan projects, including the “Dark Knight” Batman trilogy and “Inception.”

For a story underpinned by complex science, Murphy said in July that he “didn't really waste too much time on the physics,” to prepare for the role, instead honing in on “the humanity and the emotion, and the complexity and the morality of the character.”

"Oppenheimer" led this year’s Oscar nominations and has triumphed at other awards ceremonies including the Golden Globes. The movie – which, alongside Greta Gerwig’s “Barbie,” birthed the summer cinema phenomenon dubbed “Barbenheimer” – helped prop up a 2023 box office where well-established franchises fell flat.