Paul Thomas Anderson’s counter-culture caper One Battle After Another has won the Oscars war, taking home six awards after a hotly contested season.

The big-budget comedy thriller, inspired by Thomas Pynchon’s Vineland, was named best picture and also won director, supporting actor for Sean Penn, adapted screenplay, editing and the first ever Oscar for casting, a category long-petitioned for within the industry.

“I wrote this movie for my kids to say sorry for the housekeeping mess we left in this world we’re handing off to them,” Anderson said in his first acceptance speech of the night. He also said he hoped a younger generation would help bring back “common sense and decency” to society.

Previously nominated for films including Boogie Nights, There Will Be Blood and Phantom Thread, tonight marks Anderson’s first ever Oscar wins.

Penn beat out his co-star Benicio del Toro for his third Oscar win but wasn’t in attendance to accept his award. “Sean Penn couldn’t be here tonight or didn’t want to,” presenter Kieran Culkin joked.

The season had became a two-horse race between One Battle After Another and Sinners, which entered the night as the most-nominated film ever with a record 16 nominations.

The period vampire blockbuster won four awards: actor for Michael B Jordan, original screenplay, original score and cinematography, which makes Autumn Durald Arkapaw the first ever female winner and first Black winner of the award.

Jordan won his first Oscar for his lead performance in the film, beating Timothée Chalamet and Leonardo DiCaprio. “I stand here because of the people who came before me,” he said before listing Black Oscar winners in the past. He has become the sixth Black winner in this category.

Coogler is only the second Black winner of the original screenplay Oscar, following in the footsteps of Jordan Peele, who won for Get Out. The 39-year-old made his cast stand up telling them “you all are winners in my book” and apologised to his children “for all the time away”.

Jessie Buckley became the first ever Irish winner of the best actress Oscar for her performance in Chloé Zhao’s Shakespeare drama Hamnet. The 36-year-old was previously nominated for her role in The Lost Daughter.

She devoted the award to “the beautiful chaos of a mother’s heart” and called it “the greatest honour”.

Amy Madigan was named best supporting actress for her villainous role in hit horror Weapons, beating Teyana Taylor and Wunmi Mosaku. It was the first time the award was won by an actor who was the only nominee from their film since Penelope Cruz in Vicky Cristina Barcelona. The 75-year-old actor, who was previously nominated in 1986, set a new record for the longest gap between nominations before a win.

Joachim Trier’s family drama Sentimental Value was named best international feature film, the first time that Norway has won in this category. It beat out The Secret Agent, It Was Just an Accident and The Voice of Hind Rijab. “I’m just a film nerd from Norway,” Trier said on stage. At the end of his speech, he paraphrased James Baldwin, saying: “all adults are responsible for all children and lets not vote for politicians who don’t take this seriously into account”.

The award was co-presented by Javier Bardem who said “no to war and free Palestine” on stage, while wearing prominent badges expressing the same messaging.

The Oscar for best documentary went to Mr Nobody Against Putin which tells of a teacher fighting against oppressive rules being introduced in his Russian school, a film which co-director David Borenstein said is “about how you lose your country”. He added: “When a government murders people on the streets of our major cities, when we don’t say anything, when oligarchs take over the media and control how we could produce it and consume it, we all face a moral choice, but luckily, even a nobody is more powerful than you think.”

KPop: Demon Hunters, Netflix’s most watched film ever, won two Oscars for animated feature and original song. This week saw official confirmation that a sequel was on the way. “For those of you who look like me, I’m so sorry that it took us so long to see us in a movie like this,” co-director Maggie Kang said before devoting the win to Korea and “for Koreans everywhere”. Smash hit Golden made history as the first k-pop song to win an Oscar.

Guillermo del Toro’s Netflix take on Frankenstein also won three awards for production design, costume design and makeup and hairstyling. The Oscar for visual effects went to Avatar: Fire and Ash while F1 took home the award for sound.

There was also an unusual tie in the category for live action short, only the seventh time in Oscars history this has happened. The last time was in 2012 for sound editing.

It marks a major night for Warner Bros with the studio taking home 11 awards and the first best picture win since Argo in 2013. The epic night for the studio arrives as Paramount prepares to merge after a heated battle for ownership.

Conan O’Brien returned as host for the second year in a row and kicked off the show with a pre-recorded bit dressed as Madigan’s character in Weapons, racing through scenes from the year’s big films. He joked that he will be “the last human host” of the Oscars (while hosting the animated short award, Will Arnett also made an impassioned plea against the use of AI which received roaring applause).

He said anyone offended by politics during the ceremony should watch the “alternate Oscars being hosted by Kid Rock”, poked fun at Netflix CEO Ted Sarandos being there for “his first time in a theatre”, referenced the lack of British lead acting contenders by saying a spokesperson said “well at least we arrest our paedophiles” and quipped about Amazon’s lack of nominations by asking “why isn’t the website I buy toilet paper from winning more Oscars?”.

O’Brien also spoke about the “very chaotic frightening times” we’re in and how the awards are “particularly resonant” given the many international nominees. “Let us celebrate not because we think all is well but because we work and hope for better in the days ahead,” he added.

Later in the night he also joked that he was coming live from the “has a small penis theatre” before joking “let’s see him put his name in front of that”. When hosting the two documentary Oscars, Jimmy Kimmel also took aim at Amazon’s Melania doc (“Oh mad is he gonna be mad his wife wasn’t nominated for this”) and the ongoing right-wing takeover of media (“As you know, there are some countries whose leaders don’t support free speech. I’m not at liberty to say which. Let’s just leave it at North Korea and CBS”).

The night also saw a special tribute to the late Rob Reiner led by long-time friend and collaborator Billy Crystal. He said his films will “last for lifetimes” and the loss of Rob and wife Michelle is “immeasurable”. He was then joined by other stars from his films including Meg Ryan, Carol Kane, Demi Moore and Annette Bening.

Rachel McAdams also remembered fellow Canadian Catherine O’Hara (“made us laugh until we cried”) and her Morning Glory co-star Diane Keaton (“luminous on screen and indelible in life”) both of whom died in the last year.

Barbra Streisand followed with a tribute to the late Robert Redford, an “intellectual cowboy” who had “real backbone on and off the screen”. She also sang a section of The Way We Were, the title track from their much-loved romantic drama.

Nominated films which came away empty-handed tonight included Bugonia, Train Dreams, It Was Just an Accident and The Secret Agent.

Last year’s Oscars were led by major wins for Sean Baker’s low-budget comedy drama Anora which was named best picture and picked up four other awards.