The network responded swiftly to a news segment Monday where Michael Knowles of "The Daily Wire" said the 16-year-old environmentalist was a "mentally ill Swedish child who is being exploited by her parents and by the international left".
Knowles was immediately called out by a fellow guest, podcast host Chris Hahn, who said: "You're a grown man and you've attacked a child. Shame on you."
The network later apologised to Thunberg and viewers for the comment and said it had no plans to book Knowles, who has no tie to the network, again.
A couple hours later Ingraham, one of the network's prime-time stars, said she found some of Thunberg's remarks before the United Nations that scolded officials for not acting on climate change to be chilling.
She juxtaposed a portion of the speech with a clip from the 1984 horror film Children of the Corn. Based on a King story, the film is about children in a Nebraska town being persuaded to kill the adults.
"I can't wait for Stephen King's sequel 'Children of the Climate',"' Ingraham said.
In an interview last week, Thunberg said that she takes personal criticism as proof that activists are making a difference.
"You just have to ignore them because they are just so desperately trying to remove the focus from the climate crisis to make it become something about me as an individual," she said.
"When they do that, I mean, they don't have any arguments left."