Cillian Murphy Ends 'Exhilarating' “Oppenheimer ”Journey with His First Oscar Win: 'I'm a Proud Irish Man'

Bradley Cooper, Colman Domingo, Paul Giamatti and Jeffrey Wright were all nominated alongside the 'Oppenheimer' star at Sunday's Academy Awards

Cillian Murphy just nabbed his first-ever Academy Award.

The Oppenheimer star, 47, won Best Actor at Sunday's 2024 Oscars thanks to his performance as J. Robert Oppenheimer, the father of the atomic bomb, in Best Director winner Christopher Nolan-directed biopic.

In his acceptance speech, Murphy thanked Nolan, 53, the Academy and more, admitting he was feeling "a little overwhelmed" at the honor.

"It's been the wildest, most exhilarating, most creatively satisfying journey you've taken me on over the last 20 years. I owe you more than I can say," he continued. "Thank you so much [to] every single crew member, every single cast member, on Oppenheimer; you guys carried me through. All my fellow nominees, I remain in awe of you guys. Truly."

Related: Christopher Nolan's Oppenheimer Named Best Picture at 2024 Oscars in Impressive Awards Season Sweep

The actor went on to thank his "incredible team" and his family, including wife of nearly 20 years Yvonne McGuinness and their sons Malachy, 18, and Aran, 16, who were in the audience. "I love you so much, and I'm a very proud Irish man standing here tonight," he said.

Murphy concluded, "We made a film about the man who created the atomic bomb. And for better or for worse, we're all living in Oppenheimer's world, so I would really like to dedicate this to the peacemakers everywhere."

The other nominees in the Best Actor category were Bradley Cooper for Maestro, Colman Domingo for Rustin, Paul Giamatti for The Holdovers and Jeffrey Wright for American Fiction.

Related: Oscars 2024 Winners List: Oppenheimer Leads with 7 Awards Followed by Emma Stone's Poor Things

The summer blockbuster Oppenheimer has produced several award-winning performances, including Murphy in the title role, his first lead part with longtime collaborator Nolan.

The Peaky Blinders star's portrayal of Oppenheimer’s moral dilemmas earned him critical acclaim, and he raked in wins at the Golden Globes, BAFTAs and SAG Awards earlier this year, among other assorted accolades.

Costar Robert Downey Jr. — who picked up the Best Supporting Actor Oscar on Sunday — previously told PEOPLE that he has "never witnessed a greater sacrifice by a lead actor in my career" than what Murphy pulled off.

"He knew it was going to be a behemoth ask when Chris called him. But I think he also had the humility that is required to survive playing a role like this," added Downey, 58, whose portrayal Atomic Energy Commission Chairman Lewis Strauss scored him his first Oscar 31 years after his Best Actor nomination for Chaplin.

Related: Bradley Cooper Pokes Fun at His Own ‘Crazy Demands’ as Maestro Director: ‘We Were Losing Our Minds’

Fellow nominee Cooper, 49, earned his fifth acting nod at the Academy Awards for his portrayal of legendary conductor Leonard Bernstein in Maestro.

The biopic depicts Bernstein’s marriage to Felicia Montealegre, played by Carey Mulligan, and was made with the approval of Montealegre and Bernstein’s children Jamie, Alexander and Nina.

Over this past awards season, Cooper picked up several nods for his work on Maestro. He was nominated at the Golden Globes, Critics Choice Awards, BAFTAs and SAG Awards. He also garnered praise as the film’s director and co-writer.

Maestro earned a total of seven nominations ahead this year’s Academy Awards ceremony, including Best Picture and Best Original Screenplay.

Related: Da'Vine Joy Randolph's Oscar Win Reduces Audience to Tears: 'I Thank You for Seeing Me'

Giamatti, 56, stars alongside Dominic Sessa and newly minted Oscar winner Da’Vine Joy Randolph in Alexander Payne's dramedy The Holdovers. As strict boarding school teacher Paul Hunham, Giamatti received acclaim for his delivery of a poignant arc.

The Sideways actor has had a dream awards season, nabbing a Critics Choice win and a third Golden Globe, as well as BAFTA and SAG Award nods. He was last nominated at the Oscars 18 years ago, for Best Supporting Actor in 2005’s Cinderella Man.

Before attending his dad's alma mater for undergraduate and graduate degrees, a teen Giamatti attended a boarding school “very similar” to the one in The Holdovers, he previously told PEOPLE.

“There's a wealth of stuff I'm drawing from my own past with this character," he said.

Related: Colman Domingo Says He Has Room for ‘Two Oscars’ Next to His ‘Euphoria’ Emmy (Exclusive)

Domingo, 54, received his first Oscar nod at this year’s ceremony for his role as Bayard Rustin, a civil-rights activist who worked closely with Martin Luther King Jr. to organize the March on Washington.

The Emmy-winning Euphoria actor's performance in Rustin notched him nominations at the Golden Globes, BAFTAs and SAG Awards.

Domingo, who has Belizean and Guatemalan heritage, is the first Afro Latino to ever be nominated for Best Actor.

Related: How Jeffrey Wright Returned to Regular Dad Duties After Receiving American Fiction Oscar Nomination (Exclusive)

In American Fiction, Wright portrays writer Thelonious “Monk” Ellison, a frustrated novelist who writes a stereotypically Black book out of spite, only for it to become his best-selling work.

Based on Percival Everett’s 2001 novel Erasure, the comedy follows Monk as he navigates the repercussions of the book on his career and family.

Wright, 58, notched his first Oscar nomination for his critically acclaimed performance as Monk. Throughout awards season, he has raked in nominations at the Golden Globes, Critics Choice and SAG Awards.

American Fiction has five total Oscar nods, with Sterling K. Brown recognized for his supporting role and the film up for Best Picture, Best Adapted Screenplay and Best Original Score.

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The 96th Academy Awards are airing live on ABC from the Dolby Theatre in Hollywood, California.

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