"A total loser!" Trump tweeted, in response to a post from campaign manager Brad Parscale about George Conway - who despite his wife's senior role in the administration has emerged as an outspoken Trump critic.
Conway frequently interacts with Washington media figures on Twitter by criticizing the president, despite his wife's position at the White House.
Mr. Conway had launched a barrage of insults at the president on Monday evening, tweeting medical definitions of personality disorders including "deceitfulness" and grandiosity as symptoms - and saying they apply to the 45th president.
George Conway, who withdrew from consideration for a Justice Department job in June 2017, trolled Trump after the president tweeted or retweeted more than 50 times over the weekend.
"No, I don't share those concerns", Kellyanne Conway told reporters Monday of her husband's criticism of Trump's mental health.
George Conway hasn't responded to Parscale's post.
Kellyanne Conway has made a name for herself as one of Donald Trump's toughest, sharpest defenders.
Conway himself responded shortly afterward, tweeting: "Congratulations!"
After Burger King poked fun at the president for his mistake, George Conway wrote in a searing tweet: "Think of how much of a laughingstock a president has to become to have *Burger King* make fun of him". You're just jealous of Donald Trump Jr.,' really!? Things took a turn after that when Scarborough suggested Mrs. Conway holds contempt for Trump, which she expressed publicly before joining his team, and now she's asking her husband to carry them for her.