Two months ago, Roseanne Barr was a star again.
Her sitcom “Roseanne” returned in March after a two-decade absence to enormous ratings on ABC. Network executives were celebrating their strategy of appealing to wider swaths of the country after Donald J. Trump’s surprising election win and the president himself called Ms. Barr to congratulate her on the show’s large audience.
But on Tuesday, that all came crashing down. ABC abruptly canceled “Roseanne” hours after Ms. Barr, the show’s star and co-creator, posted a racist tweet about Valerie Jarrett, an African-American woman who was a senior adviser to Barack Obama throughout his presidency and considered one of his most influential aides. Ms. Barr wrote if the “muslim brotherhood & planet of the apes had a baby=vj.”
Ms. Barr later apologized, but it was too late. In announcing the show’s cancellation, ABC’s entertainment president, Channing Dungey, said in a statement that “Roseanne’s Twitter statement is abhorrent, repugnant and inconsistent with our values.”
The show had ended its successful comeback season last week and was expected to return in September for a 13-episode run. Robert A. Iger, the chief executive of the Walt Disney Company, ABC’s corporate parent, shared Ms. Dungey’s statement on his own Twitter account, adding: “There was only one thing to do here, and that was the right thing.”
The sudden cancellation of a hit show — it had the highest ratings of a new TV series in years — because of offscreen controversy was almost without precedent.
The show brought in an estimated $45 million of advertising revenue for ABC this year, and the network likely would have collected more than $60 million next season, according to Kantar Media.
The move was decided by top Disney and ABC executives, including Ms. Dungey who was appointed to herrole in February 2016, becoming the first black entertainment president of a major broadcast television network. She had the backing of Ben Sherwood, the head of ABC’s television group, and Mr. Iger, who was involved in the process starting very early on Tuesday, according to two Disney insiders who spoke on the condition of anonymity to describe company matters.