ABC immediately renewed the show for a second season last Friday. Then, mere hours later, Barr sent social media into a frenzy when she tweeted that Trump has "freed so many children held in bondage to pimps all over the world" - a debunked claim that has been circulating on far-right sites.
Barr deleted the tweet, but it was a stark reminder that the network had indefinitely tethered itself to an extremely controversial figure - and given her a powerful megaphone.
"If this has had happened five years ago, people may have laughed it off. But people are not laughing about this anymore," said Bonnie Fuller, president and editor-in-chief of the entertainment website Hollywood Life. "There have been too many consequences from fake news and conspiracy theories."
It wasn't the first time Barr's tweets recently landed her in hot water. On the day of the Roseanne premiere, she accused teenage school shooting survivor David Hogg of giving a Nazi salute. Barr later retracted the claim and said she was misled by a doctored image.
At the Television Critics' Association Press tour last summer, a reporter posed this scenario to ABC entertainment president Channing Dungey, as Barr was already known for tweeting fringe conspiracy theories: "Is there somebody whose job it is to monitor her Twitter feed in absolute terror in case she says something that's going to make this new show untenable?" When Dungey replied that Barr planned to turn the keys to her Twitter account over to her son, the reporter pressed: "No matter who is actually doing her Twitter feed, if you look at the things that whoever it is has tweeted in the past week, there's wacky conspiracy stuff that either she or her son has tweeted, and it's not like this is a new thing. I'm just wondering if that concerns you."
"I try to just worry about the things that I can control," Dungey said, eliciting laughter in the room.
ABC declined to comment for this story, and according to industry experts, that's the typical decision in the TV controversy playbook.
"They're smart people over there [at ABC]. They knew," said Preston Beckman, a veteran broadcast executive and media consultant who worked at NBC and Fox. "She was controversial the last time, so it's not like they thought they were getting an angel.
"I think that any network who says, 'Gee, had I known what she tweets or that there were pictures of her allegedly dressed up like Hitler, we wouldn't have gone near it,' they're lying to you."
Indeed, Barr appeared on the cover of Jewish magazine Heeb in 2009, dressed like Hitler while holding a tray of burned cookies shaped like people. Although it was explained as "satire", that didn't really help when those images flew around social media without context.
When the Hollywood Reporter this week asked Roseanne co-showrunner Bruce Helford about seeing the star of his show dressed as a Nazi, he noted Barr is a "staunch supporter of Israel" and added that he assumed it was a parody.
"My feeling is that people should just watch the show and judge it on its merits," Helford said, emphasising that Barr's real-life persona is separate from her character.
Beckman said that although ABC doesn't have to make any excuses for Barr's behaviour, "there's always a line you don't want to cross".
"Once you cross that line, there are consequences. But I think to her fans, and her kind of going against the grain and not acting like a typical TV star, is the reason why she's popular with them."
Plus, viewers don't necessarily care about the behaviour of stars off-camera.
"Viewers look to TV not for its politics but for its entertainment," TV historian Tim Brooks said. "If it's a funny show, they'll forgive a lot."
Also worth noting is that no matter the backlash to Barr in real life, it's giving the network what it wants: attention.
