Diane Jansen says she stopped to report the truck parked in the bike lane but took a video instead when driver became angry. The man is shown in the video swearing and throwing something at Jansen.
Once the video showed up on YouTube and other social networks, cyclists around Toronto publicized the video with the hashtag #biketo.
Canada Post spokesman Jon Hamilton says he saw the video of the confrontation on Twitter and immediately reached out to the cyclist to apologize.
"The behaviour demonstrated by the employee in the video is completely unacceptable," he said. "We reached out to the individual who posted the video online to apologize and thank her for bringing the matter to our attention. We were able to quickly identify the employee and take the appropriate action."
Hamilton could not say whether the employee was dismissed or disciplined. Canada Post does not publicize personnel matters, he said.