The announcement caps a roller coaster week for the film star and stand-up comic, who was first celebrating the high-profile gig just a couple of days ago.
"I am blown away simply because this has been a goal on my list for a long time," he said Tuesday afternoon. "To be able to join the legendary list of [hosts] that have graced that stage is unbelievable."
But that elation did not last long before it became laced with controversy.
Benjamin Lee, an editor at The Guardian, immediately expressed his disappointment with the selection and soon pointed to a cluster of old tweets that had been directed harsh words toward the gay community.
"Yo if my son comes home & try's 2 play with my daughters doll house I'm going 2 break it over his head & say n my voice 'stop that's gay,' " reads one tweet that Hart posted in 2011.
That wasn't the only one. Other users dredged up a number of posts dating back nearly a decade, in which Hart spoke of gay people negatively and used an anti-gay slur.
"Hart's obsession with making unfunny, disrespectful and inappropriate jokes about a community he has shown nothing but bile for along with a string of unrepentant responses to any criticism paints him as someone entirely undeserving of a spot on the Oscars stage," Lee argued Wednesday.
The controversy only ballooned from there on social media, and by Thursday afternoon, Hart responded to it in two videos posted to his Instagram account.
"My team calls me, 'Oh my God, Kevin, the world is upset about tweets you did years ago,' " he said in the first, rubbing his face in evident frustration. "Guys, I'm almost 40 years old. If you don't believe that people change, grow, evolve as they get older, I don't know what to tell you."
In the second, posted just a few hours later, he said he had gotten a call from the Academy of Motion Picture Arts and Sciences, the organization behind the Oscars, requesting that he apologize for his tweets.
"I passed on the apology. The reason why I passed is that I've addressed this several times. This is not the first time this has come up. I've spoken on it. I've said where the rights and wrongs were. I've said who I am now versus who I was then," he said. "I'm not going to continue to go back and tap into the days of old when I've moved on and I'm in a completely different space in my life."
"I'm thankful and appreciative of the opportunity," he added. "But if it goes away, no harm, no foul."
Shortly afterward, Hart announced he was stepping down.
The Academy did not immediately offer public comment on the situation. This year's Oscar nominees are expected to be announced on Jan. 22, while the ceremony is scheduled for Feb. 24.
Copyright 2018 NPR. To see more, visit https://www.npr.org.