Barr took to Twitter to apologize for the racist slur saying, "I apologize to Valerie Jarrett and to all Americans". The maker of Ambien, Sanofi, issued a statement on Wednesday morning saying racism was not a side effect of the sleep aid.
The Monday tweet that got Roseanne into trouble read, "Muslim brotherhood & planet of the apes had a baby=vj".
Barr was resoundingly condemned Tuesday, including from many who helped make her show successful.
Ms Jarrett, 61, was a top aide for Mr Obama and also served as assistant to the president for public engagement and chair of the White House council on women and girls, as well as leading his transition team when he moved into the White House.
"I did something unforgiveable so do not defend me", Barr wrote.
Williams also called out Barr's attempt to defend herself by tweeting, "It was 2 in the morning and I was Ambien tweeting - it was Memorial Day".
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Her daughter Laura is a justice reporter for news network CNN. "Forgive me - my joke was in bad taste". "I BLAME MYSELF OK? it's just an explanation not an excuse, Ok, bully?" "I should have known better".
And Barr pointed a finger at Wanda Sykes, the show's consulting producer, for ultimately causing the show's demise. Others believe that her personal comments on Twitter should not have impacted the sitcom. "Nice!" Sara tweeted that she was "disappointed" in her onscreen mom and blasted Roseanne's comments as "abhorrent".
"I want to mention Bob Iger, who is the CEO of Disney, called me before the announcement", Jarrett, 61, said. The post said she went too far, it was "egregious indefensible" and asked people "don't defend it please".
And she said she thinks the reason ABC pulled the plug was a threatened boycott by advertisers. But much of its progress would have been threatened if it looked the other way at Barr's tweet. "Today my words caused hundreds of hardworking people to lose their jobs", Barr wrote in a tweet, one in a series of posts Tuesday night. The talent representative says it has ended its relationship with Barr "effective immediately". Several networks said it was removing reruns of her show.