The director Alan Schneider, who was an early collaborator with the playwrights Samuel Beckett and Edward Albee, saw a London run-through of Weller's play Moonchildren, and brought it to the Arena Stage in Washington then to Broadway. Moonchildren subsequently had an acclaimed run off-Broadway at the Theatre de Lys in 1973 and 1974. Schneider also staged Weller's play Loose Ends at the Arena Stage then on Broadway at Circle in the Square Theatre.
His play Spoils of War was adapted as a screenplay and became the TV film In Spite of Love. Kate Nelligan played the part of Elise in both.
In 2017 Brandeis University honored Weller with the university's Brandeis Creative Arts Award. The university invited him to write a new play and suggested it might explore issues regarding freedom of speech. The university had recently received the papers of the social-satirist and stand-up comedian Lenny Bruce. Weller researched the library's collection of the Bruce papers, and began to write his play Buyer Beware, a play that poses the question: If Lenny Bruce were to come back, and book a gig on a campus of today, what would happen?