Its plot follows a stage actress who, after witnessing the accidental death of a fan, struggles through a nervous breakdown while she prepares for an upcoming Broadway premiere.

In New Haven, Connecticut, Myrtle Gordon is a famous but troubled middle-aged actress performing out-of-town previews of a new play called The Second Woman before its Broadway run.

Over the course of numerous performances, Myrtle departs from the play's script in myriad ways, including changing her lines, throwing props around the set, breaking the fourth wall, and collapsing on stage.

In the way that it drapes Gena Rowlands in long, black, specter-like capes and collars—and the primal world around her colored in bright, bloody reds—it turns a funhouse mirror onto the crushing, almost satanic rituals of film acting and movie star culture like in Mulholland Drive.

After a number of preview screenings, it opened on December 25, 1977, at the Fox Wilshire Theater, Los Angeles where it played to almost empty houses, and closed in February having never been commercially shown elsewhere.

The review in Variety that appeared after a press screening concluded, "One must question whether more than a handful of moviegoers are interested in the effort, whether audiences have not already seen enough of Cassavetes' characters ...

It currently holds a 96% "fresh" rating on Rotten Tomatoes from 27 reviews; the consensus states: "Opening Night is as dense and difficult as one would expect from John Cassavetes, but even the director's detractors will be unable to deny the power of Gena Rowlands' performance.

Back to the Beat, an EP from the band, Motion City Soundtrack, features a song titled "Opening Night", in reference to the film.

Jessica Pratt cited the film as an influence on her album Quiet Signs and titled the instrumental first track "Opening Night."

[11] Rufus Wainwright and Ivo van Hove adapted the film into a musical, which premiered at the Gielgud Theatre in London's West End in March 2024.