“I was out of line and I was wrong,” said Smith, who hit Rock at the Oscars after the comedian made a joke about his wife. The film organization opened an inquiry into the incident. Will Smith walked onstage and slapped Chris Rock after the comedian made a joke about Mr. Smith’s wife, the actress Jada Pinkett Smith. Mr. Smith then yelled and cursed at Mr. Rock after returning to his seat.Ruth Fremson/The New York TimesLOS ANGELES — Will Smith apologized to the comedian Chris Rock on Monday evening for slapping him during Sunday night’s Oscars telecast after the Academy of Motion Picture Arts and Sciences, which administers the awards, denounced his actions and opened an inquiry into the incident.Mr. Smith, who had pointedly not apologized to Mr. Rock on Sunday night when he accepted the award for best actor, wrote on Instagram Monday evening that “I would like to publicly apologize to you, Chris.”“I was out of line and I was wrong,” he said in the statement. “I am embarrassed and my actions were not indicative of the man I want to be.”His apology came as the academy, a major Hollywood union and others criticized his actions, which stunned viewers around the world and overshadowed the Oscars. “The academy condemns the actions of Mr. Smith at last night’s show,” the film organization said in a statement. “We have officially started a formal review around the incident and will explore further action and consequences in accordance with our bylaws, standards of conduct and California law.”The academy’s statement came after a meeting Monday. A five-page document on standards of conduct that accompanied it spells out behavior the organization deems unacceptable. It prohibits “physical contact that is uninvited and, in the situation, inappropriate and unwelcome, or coercive sexual attention.” Also not allowed is “intimidation, stalking, abusive or threatening behavior, or bullying.”Disciplinary action, according to the bylaws, could include “suspension of membership or expulsion from membership.”The Academy was not known to have expelled a member before 2017, when Harvey Weinstein was removed amid allegations of sexual harassment and rape. Then, in 2018, after adopting a code of conduct for members, the organization expelled Bill Cosby, who had been convicted of sexual assault, and the filmmaker Roman Polanski, who had fled the country years earlier while awaiting sentencing for statutory rape.The Screen Actors Guild-American Federation of Television and Radio Artists, the union representing thousands of people who work in film, television and radio, called the incident “unacceptable” but said that it “does not comment on any pending member disciplinary process.”“Violence or physical abuse in the workplace is never appropriate and the union condemns any such conduct,” the union said in a statement Monday. “The incident involving Will Smith and Chris Rock at last night’s Academy Awards was unacceptable.”How to Understand the Altercation Between Will Smith and Chris RockThe Incident: The Oscars were derailed when Will Smith slapped Chris Rock, who made a joke about Mr. Smith’s wife, Jada Pinkett Smith.His Speech: Moments after the onstage altercation, Mr. Smith won the Oscar for best actor. Here’s what he said in his acceptance speech.The Aftermath: Mr. Smith apologized to Mr. Rock the next day after the Academy denounced his actions and opened an inquiry into the incident.A Triumph Tempered: Mr. Smith owned Serena and Venus Williams’s story in “King Richard.” Then he stole their moment at the Oscars.What Is Alopecia?: Ms. Smith’s hair loss condition played a major role in the incident.The incident unfolded Sunday night after Mr. Rock made a joke about the buzzed hair of Mr. Smith’s wife, Jada Pinkett Smith, who has alopecia, a condition that leads to hair loss. Mr. Smith responded by walking onto the stage of the Dolby Theater and slapping Mr. Rock, leaving stunned viewers wondering at first if the blow might have been scripted until Mr. Smith returned to his seat and warned him to stop talking about his wife, using expletives.Jada Pinkett Smith and Will Smith in the audience at the ceremony.Ruth Fremson/The New York TimesBehind the scenes at the Oscars, there were serious discussions about removing Mr. Smith from the theater, according to two industry officials with knowledge of the situation who were granted anonymity to describe internal deliberations. But time was short, because the best actor award, which Mr. Smith was heavily favored to win, was fast approaching, one noted — and stakeholders had varying opinions on how to proceed. There was also concern about further disrupting the live broadcast, the other said.As the show went on, the actor Denzel Washington spoke with Mr. Smith during a commercial break. Not long after that Mr. Smith won best actor. (Mr. Smith said in his speech that Mr. Washington had told him: “At your highest moment, be careful. That’s when the devil comes for you.”) In his onstage remarks, Mr. Smith apologized to the academy and to his fellow nominees — but not to Mr. Rock — and defiantly sought to draw parallels to the character he played in “King Richard,” the father of Venus and Serena Williams.“Richard Williams was a fierce defender of his family,” Mr. Smith said.He received a standing ovation.Mr. Smith said in his statement Monday that he had reacted emotionally because a joke about his wife’s medical condition was “too much for me to bear.” Mr. Smith also apologized to the Academy, the show’s producers, the viewers, the people who worked on “King Richard” and the Williams family.“I deeply regret that my behavior has stained what has been an otherwise gorgeous journey for all of us,” he said. “I am a work in progress.”The incident overshadowed the awards. On ABC’s “Good Morning America,” on Monday George Stephanopoulos described it as “something we have never seen before, something that is very hard to process: Will Smith, walking up onto that stage after Chris Rock told a joke about his wife — simply assaulting Chris Rock.”The powers-that-be at the Oscars had been intent on not repeating last year’s record-low ratings, putting a series of changes in place they had hoped would draw more viewers: installing three comic actresses as hosts, pretaping some awards to try to quicken the pace, introducing a fan-favorite award that viewers could vote on. But the broadcast became must-see television for a reason they did not anticipate.“Welp … I said it wouldn’t be boring #Oscars,” Will Packer, one of the show’s producers, tweeted after the show. He later added: “This was a very painful moment for me. On many levels.”The telecast drew a larger audience than last year’s, but interest remained depressed compared with past years. The awards show attracted 15.4 million viewers on ABC, a 56 percent improvement on the 9.85 million people who watched the 2021 event, according to ABC. Sunday night’s show was still the second least-watched Oscars ever.Comedians, who tell uncomfortable and sometimes offensive jokes for a living, raised concerns about the precedent Smith had set.“Let me tell you something, it’s a very bad practice to walk up onstage and physically assault a comedian,” Kathy Griffin tweeted. “Now we all have to worry about who wants to be the next Will Smith in comedy clubs and theaters.”Jimmy Kimmel, the comedian and talk show host who had been the last person to host the Oscars, said on “The Bill Simmons Podcast” that he felt bad for the show’s hosts; for Ahmir “Questlove” Thompson, who won the best documentary feature award Mr. Rock had been presenting, and for Mr. Rock, who he said “certainly didn’t deserve that.”“In a way, I feel bad for Will Smith too, because I think he let his emotions get the better of him, and this should have been one of the great nights of his life,” Mr. Kimmel said. “And now it’s not. Was there anyone who didn’t like Will Smith an hour ago in the world? Like no one, right? Now he doesn’t have a single comedian friend — that’s for sure.”Whoopi Goldberg, who is on the academy’s board of governors and has hosted the show several times, said on “The View” on Monday that she did not think Smith’s award would be revoked, citing Mr. Rock’s decision not to press charges.“We’re not going to take that Oscar from him,” she said. “There will be consequences, I’m sure.”Mr. Rock after the incident with Mr. Smith, seated in front of him. Ruth Fremson/The New York TimesThe Los Angeles Police Department said it was aware of what it described as an incident involving “one individual slapping another” at the Oscars. The police said the person involved had “declined to file a police report.”“If the involved party desires a police report at a later date,” the police said, they would move forward and “complete an investigative report.”At least one member of the academy, Marshall Herskovitz, a former president of the Producers Guild of America, called for Mr. Smith to face disciplinary action.Two industry officials said that Mr. Rock’s joke had apparently been ad-libbed.And Bruce Vilanch, a past head writer of Oscars shows who did not work on this year’s, said: “Everything that is in the script is vetted. But if a comedian comes out onstage and ad-libs something, there’s no time to vet. I’m guessing that’s what happened last night. What I’m hearing from everybody is that this was not the material that was rehearsed.”Mr. Rock has teased the Smiths from the Oscars stage before. In 2016, when the Smiths boycotted the awards show because the nominees in the four acting categories were all white, Mr. Rock, that show’s host, joked about it. “Jada says she not coming, protesting,” he said. “I’m like, ain’t she on a TV show? Jada is going to boycott the Oscars — Jada boycotting the Oscars is like me boycotting Rihanna’s panties. I wasn’t invited.”Mr. Smith was not deterred from celebrating his win on Sunday night, dancing at a crowded party after the Oscars while holding his trophy, but he avoided questions about the incident. A publicist for Mr. Rock did not immediately respond to requests for a comment.Jaden Smith, one of the Smiths’ children, tweeted simply: “And That’s How We Do It.”The reaction inside and outside Hollywood ranged widely. In interviews following the show, at after-parties and on social media, Smith’s colleagues variously expressed sadness, confusion, disbelief, anger and, in some cases, empathy. Many deflected or ignored questions about the episode entirely.The actor Mark Hamill called it the ugliest Oscars moment. “Stand-up comics are very adept at handling hecklers,” he wrote on Twitter. “Violent physical assault … not so much. #UgliestOscarMoment_Ever.”One top studio executive, who declined to speak on the record, voiced disappointment in Smith and in the fact that the audience in the theater gave him a standing ovation.And Janai Nelson, the president of the NAACP Legal Defense and Education Fund, worried aloud in a tweet that “the way casual violence was normalized tonight by a collective national audience will have consequences that we can’t even fathom in the moment.”Others seemed to defend Mr. Smith. “Many takes on here about Will Smith and Chris Rock, especially from people whose partners are not Black women (mainly white people),” the author Frederick Joseph tweeted. “I don’t care if it’s a joke or not, the amount Black women have to endure — people are tired of it. We have no idea what Jada has gone through.”And the comedian Tiffany Haddish, who starred in the movie “Girls Trip” with Ms. Pinkett Smith, said in an interview with People magazine at an after-party that she appreciated seeing Mr. Smith protect his wife.“Maybe the world might not like how it went down,” Ms. Haddish said, “but for me, it was the most beautiful thing I’ve ever seen because it made me believe that there are still men out there that love and care about their women, their wives.”Even still, the day after, the prevailing reaction was mostly one of disbelief.“We’re not sure where the fallout will end up,” Ryan Seacrest said Monday on his morning show “Live With Kelly and Ryan.” “It was one of those moments that we couldn’t believe when we saw it.”Sperling reported from Los Angeles. Matt Stevens and Julia Jacobs reported from New York. More