Smith is also not permitted to attend any other events held by the Academy of Motion Picture Arts and Sciences over the next decade.
Academy governors convened on Friday morning to discuss actions against Smith, with board members Steven Spielberg and Whoopi Goldberg among those invited to rule on the actor's fate.
Smith's actions during a live global broadcast stunned audiences and cast a shadow over both the night's big winners and the Tinseltown showcase event itself.
Will Smith was banned on Friday from attending the Oscars for the next 10 years, two weeks after the actor stunned the world by storming on stage mid-ceremony to slap the comedian Chris Rock.
Smith is also not permitted to attend any other events held by the Academy of Motion Picture Arts and Sciences over the next decade.
The Board's decision as set out in a letter from Academy chiefs did not revoke the best actor award Smith won last month for "King Richard," nor did it mention any ban on future Oscar nominations.
"The Board has decided, for a period of 10 years from April 8, 2022, Mr. Smith shall not be permitted to attend any Academy events or programs, in person or virtually, including but not limited to the Academy Awards," wrote president David Rubin and CEO Dawn Hudson.
Academy governors convened on Friday morning to discuss actions against Smith, with board members Steven Spielberg and Whoopi Goldberg among those invited to rule on the actor's fate.
The meeting of top brass from Hollywood's leading industry body was originally set to discuss suspending or expelling Smith, but he preemptively resigned from the group.
Actors do not need to be members of the Academy to receive nominations, although each year's Oscar nominees -- and winners -- are voted for by members of the group.
Smith's actions during a live global broadcast stunned audiences and cast a shadow over both the night's big winners and the Tinseltown showcase event itself.
"The 94th Oscars were meant to be a celebration of the many individuals in our community who did incredible work this past year; however, those moments were overshadowed by the unacceptable and harmful behaviour we saw Mr. Smith exhibit on stage," said the Academy letter.
It added: "This action we are taking today in response to Will Smith's behaviour is a step toward a larger goal of protecting the safety of our performers and guests, and restoring trust in the Academy. We also hope this can begin a time of healing and restoration for all involved and impacted."
Some had called for Smith to be stripped of his best actor Oscar, which he won for his performance in tennis biopic "King Richard" less than an hour after striking Rock on the same stage.
Rock's brother Kenny Rock told the Los Angeles Times that Smith "belittled (Chris Rock) in front of millions of people that watch the show."
But taking away Smith's award was considered unlikely, as the likes of Harvey Weinstein and Roman Polanski did not have their Oscars revoked when they were expelled from the Academy in the wake of sexual assault scandals.
Traditionally the best actor Oscar winner is invited to present the following year's best actress award -- an honour Smith will not be granted.
Smith climbed onto the Oscars stage and slapped Rock across the face in response to a joke the comic made about his wife's closely cropped hair.
Actress Jada Pinkett Smith has alopecia, a hair loss condition.
The Academy has said Smith was asked to leave the Oscars ballroom shortly after the attack.
But that claim has been disputed, including by Smith's representatives, and the show's producer Will Packer reportedly told Smith to remain and accept his statuette.
Rock was asked by Los Angeles police whether he wanted to file a report against Smith, but he declined.
"During our telecast, we did not adequately address the situation in the room," said Friday's letter from Academy chiefs.
"For this, we are sorry. This was an opportunity for us to set an example for our guests, viewers and our Academy family around the world, and we fell short -- unprepared for the unprecedented."
The letter thanked Rock for "maintaining his composure under extraordinary circumstances."
Last week, Smith apologized to Rock, describing his actions at the Oscars as "shocking, painful and inexcusable," before resigning from the Academy days later.
"I am resigning from membership in the Academy of Motion Picture Arts and Sciences, and will accept any further consequences the Board deems appropriate," said Smith -- only the fifth Black man to win the movie world's highest individual award for an actor.