Nathan Downer of Toronto all-news network CP24 was interviewing Tyson a day after the former world boxing champ visited Rob Ford at city hall amid the controversial mayor's bid for re-election next month.
"Some of your critics would say, you know this is a race for mayor. We know you're a convicted rapist, this could hurt his campaign. How do you respond to that?" Downer asked Tyson.
Tyson said he wouldn't comment on the question, but then later said, "So interesting that you come across like a nice guy but you're really a piece of s--t."
It was the first of several times he referred to Downer that way. He also used the F-word in the interview.
As Tyson continued his verbal attack, Downer reminded him they were on live TV but that did not stop him.
"I don't care," the former boxer said. "What are you going to do about it?"
In tweets to fans later, Downer said he was "OK," but acknowledged that his question had hurt Tyson's feelings.
"That was not my intention. My apologies for the language," he said.
The ex-fighter has a long history of run-ins with the law, including serving three years in prison in Indiana for the 1991 rape of a Miss Black America pageant contestant.
Tyson was in Toronto for a Wednesday night performance of his one-man show "Mike Tyson: Undisputed Truth," his first in Canada.