Newman was definitely one of the most popular recurring characters on Seinfeld, serving as Jerry's antagonist on the show. Newman worked for the post office and often was a part of Kramer's schemes.
Is that Drake's Coffee Cake?Newman
Kramer: Oh! That's Newman.
Newman: I'm on the roof!
Kramer: Well? What are you waiting for?
Kramer: You wanna shoot some pool tonight?
Newman: I can't, I'm goin' to the movies.