Cuomo had been suspended from CNN over the matter just days before his termination.
CNN said it had fired news anchor Chris Cuomo after "additional information" came to light during an investigation into his efforts to help his brother, former New York Governor Andrew Cuomo, respond to allegations of sexual misconduct.
Cuomo, who hosted CNN's most-watched prime-time news show, had been suspended on Tuesday.
He had admitted in May that he had broken some of the network's rules in advising his brother how to handle the allegations from a public relations perspective.
Andrew Cuomo was forced to step down as NY Governor in August after multiple allegations of sexual misconduct. He has denied any wrongdoing.
"Chris Cuomo was suspended earlier this week pending further evaluation of new information that came to light about his involvement with his brother's defense," the cable news network said in a statement on Saturday, but did not provide more details on what that information was.
"We retained a respected law firm to conduct the review, and have terminated him, effective immediately," it added.
Statement on Chris Cuomo’s termination from CNN. pic.twitter.com/yKPwYtMznD— CNN Communications (@CNNPR) December 4, 2021
First suspension then termination
Cuomo was initially suspended after New York Attorney General Letitia James showed text and other messages in which he sought to use his own sources in the media to find out information on the case and the women involved in it.
"He's my brother. And if I can help my brother, I do. If he wants me to hear something, I will. If he wants me to weigh in on something, I'll try," Chris Cuomo, 51, told investigators in July when asked about the counsel he had offered.
"He's my brother, and I love him to death no matter what."
A criminal complaint charging Andrew Cuomo with a misdemeanor sex offense was filed on Oct. 29 in a New York court.