Director Christopher Nolan’s film starred Irish actor Cillian Murphy as theoretical physicist J Robert Oppenheimer, leader of the United States effort in the 1940s to create a weapon devastating enough to end World War II.

Murphy won the best actor trophy, and Nolan was named best director. Emma Stone won best actress for “Poor Things”.

A three-hour historical drama about science and politics, “Oppenheimer” became an unlikely box office hit and grossed US$953.8 million, in addition to widespread critical praise.

It was the first of Nolan’s films to win best picture. The director has previously won acclaim for “The Dark Knight” Batman trilogy, “Inception”, “Memento” and other movies.

“Oppenheimer” triumphed over feminist doll adventure “Barbie,” a movie it had battled in a box office showdown dubbed “Barbenheimer”.

Other best picture contenders included “The Holdovers”, a dramedy set in a New England boarding school, and the Holocaust tale “The Zone of Interest”, which took home the best international feature film award.

In supporting actor categories, Robert Downey Jr of “Oppenheimer” and “The Holdovers” star Da’Vine Joy Randolph claimed their first Academy Awards.

“The Boy and the Heron,” Japanese director Hayao Miyazaki’s semi-autobiographical film about grief, was named best animated feature.

Winners were chosen by the roughly 10,500 members of the Academy of Motion Picture Arts & Sciences.