Opening in February 1973, Hot L Baltimore was the first major success for Wilson and his theater company, the Circle Repertory Company. Critics and audiences loved Wilson's play, and it set an Off-Broadway record of 1,166 performances after playing Off-Off-Broadway for a month.

In the play, the actors mill about in the lobby of a dilapidated old hotel, from which the "e" in the hotel sign is missing hence the name, Hot L Baltimore. The play is comprised of a series of conversations between the residents of the hotel, who are contemplating an uncertain future after the hotel is condemned and scheduled for demolition.

Wilson's play won the New York Drama Critics Circle Award for the Best American Play of 1972-73. It also won an Obie Award for best Off-Broadway play, an Outer Critics Award, and the John Gassner Playwriting award. The play was also sold to ABC and adapted as a situation comedy.