"Jeffrey Toobin, 60, who is also senior legal analyst for CNN, confirmed in a tweet that he had been sacked.
After he was suspended last month Mr Toobin said he had believed himself to be off-camera during the incident.
Vice News, which broke the initial story, reported that senior colleagues had seen Mr Toobin masturbating while apparently on a separate video call."
"I believed I was not visible on Zoom," he told Vice. "I thought no-one on the Zoom call could see me. I thought I had muted the Zoom video."