The film academy earlier condemned Smith's onstage assault of Rock. But it used stronger language today.
"Mr Smith's actions at the 94th Oscars were a deeply shocking, traumatic event to witness in-person and on television," the academy said. "Mr Rock, we apologise to you for what you experienced on our stage and thank you for your resilience in that moment. We also apologise to our nominees, guests and viewers for what transpired during what should have been a celebratory event."
On Monday, Smith issued an apology to Rock, the academy and to viewers.
Smith wrote: "Violence in all of its forms is poisonous and destructive. My behaviour at last night's Academy Awards was unacceptable and inexcusable. Jokes at my expense are a part of the job, but a joke about Jada's medical condition was too much for me to bear and I reacted emotionally."
He continued by calling his actions toward Rock "wrong" and admitting he was out of line.
"I would like to publicly apologise to you, Chris. I was out of line and I was wrong. I am embarrassed and my actions were not indicative of the man I want to be. There is no place for violence in a world of love and kindness."
Smith then issued an apology to the academy and also to the Williams family.
"I would also like to apologise to the academy, the producers of the show, all the attendees and everyone watching around the world. I would like to apologiae to the Williams family and my King Richard family. I deeply regret that my behaviour has stained what has been an otherwise gorgeous journey for all of us.
"I am a work in progress."
- Associated Press