The episode's main plot-line (George quitting his job and going back the next day pretending nothing happened) is based on Larry David's experience when he was a writer on Saturday Night Live (1975).
Newman was originally written as the African-American son of Jerry's landlord. William Thomas Jr. was cast but the role was greatly reduced during production. Tim Russ also auditioned for the role.
The trivia item below may give away important plot points.
When George quits because his boss wouldn't let him use his private bathroom, he & Jerry talk about what he could do as his next job. George says he like sports, maybe he could be a general manager of a baseball team. Actually in season 5 titled "The Opposite", he becomes Assistant to the Traveling Secretary of the New York Yankees.