According to the Academy, Will Smith was asked to leave the Oscars ceremony after hitting Chris Rock, but he refused.
Smith has also been subjected to “disciplinary proceedings,” according to the organization.
Smith slapped Rock after the comedian made a joke about his wife Jada Pinkett Smith’s shaved head, which is due to the hair-loss condition alopecia.
The actor, who won his first Oscar at the ceremony, has since apologized.
“Mr Smith was asked to leave the ceremony and refused, [but] we also recognize we could have handled the situation differently,” the Academy said in a statement.
It also announced it had “initiated disciplinary proceedings against Mr Smith for violations of the Academy’s Standards of Conduct”.
These include inappropriate physical contact, abusive or threatening behavior, and compromising the integrity of the Academy, it said.
The Academy said action may be taken at its next board meeting on 18 April. That may include “suspension, expulsion, or other sanctions,” the statement said.
It also apologized directly to Rock, as well as nominees, guests and viewers.
Meanwhile, Rock said he is “still processing” the incident in his first public comments since the ceremony.
“How was your weekend?” he jokingly asked the crowd at a stand-up show in Boston, before saying he did not plan to address the incident at length.
“I’m still processing what happened, so at some point I’ll talk about that,” Rock told the crowd. “It’ll be serious. It’ll be funny, but right now I’m going to tell some jokes.”
The incident on Sunday night happened just before Smith won the Oscar for Best Actor, when the comedian Rock was on stage to present the award for Best Documentary.
Rock made a quip about Pinkett Smith’s shaved head. The joke referred to the 1997 film GI Jane, in which Demi Moore played the title role with a severe buzzcut.
Pinkett Smith rolled her eyes at the comment, while Smith appeared to initially laugh and clap his hands before he was seen on stage, walking up to Rock.
The comedian looked stunned in the immediate aftermath of the incident, but told the audience: “That was the greatest night in the history of television.”
In his apology, Smith said his behavior was “unacceptable and inexcusable”.
“I would like to publicly apologize to you, Chris,” he said in a statement. “I was out of line and I was wrong.”