What is the name of the mailman character on Cheers?

The mailman character on Cheers is Cliff Clavin. Played by John Ratzenberger, Cliff is a know-it-all postal worker and one of the bar's most recognizable regulars.

Cliff was originally conceived as a minor character named George, but George Wendt ultimately received that role, which evolved into Norm Peterson. Ratzenberger suggested adding a resident bar know-it-all, and the producers created Cliff for the pilot. They made him a mail carrier because the occupation gave him an excuse to possess an endless supply of strange facts.

Cliff lives with his mother, Esther Clavin, and regularly irritates the other patrons with dubious trivia, exaggerated confidence, and elaborate theories. His closest drinking companion is Norm Peterson, whose beer-and-barfly habits contrast with Cliff's verbal overconfidence.

A common mix-up is confusing Cliff with Frasier Crane, another Cheers regular known for intellectual conversation. Cliff is the postal worker; Frasier is the psychiatrist. Cliff remained a recurring presence throughout the series and later appeared in the Cheers universe, including the Frasier episode “Cheerful Goodbyes.”