The Banshees of Inishern, which had been nominated in nine categories, missed out last night.
Richard Baneham won his second visual effects Oscar for his work on Avatar: The Way of Water.
The Tallaght man began his acceptance speech by saying: "Go raibh maith agat."
Northern Irish comedy-drama An Irish Goodbye won Best Live Action Short Film.
An Irish Goodbye's writer-directors, Tom Berkeley and Ross White, were joined onstage by stars James Martin and Séamus O'Hara as they accepted their Oscar.
The Banshees of Inishern, which had been nominated in nine categories, missed out last night as Everything Everywhere All at Once took home seven Oscars.
Irish film An Cailín Ciúin went home empty-handed as All Quiet on the Western Front took home the award for Best International Feature Film.
The Whale's Brendan Fraser took home the Oscar for Best Actor - the category which included Maynooth's Paul Mescal and Colin Farrell.