In San Francisco, 1998, 19-year old aspiring actor Greg Sestero meets a mysterious man named Tommy Wiseau in his acting classes with Jean Shelton. After Wiseau attempts to perform a scene from Tennessee Williams’ A Streetcar Named Desire, the performance is ripped apart by Shelton. Sestero becomes infatuated by Wiseau’s fearlessness on stage. Over the coming months, Sestero and Wiseau form a strong, albeit bizarre, friendship. Eventually, on Wiseau’s suggestion, the two move to Los Angeles to really give their acting careers a chance.
After a few weeks, Sestero signs with Iris Burton, one of the top young talent agents at the time. Wiseau, on the other hand, faces rejection from agencies, casting directors, and Hollywood insiders. During this time, Sestero develops a relationship with Amber, whom he meets at a nightclub. Wiseau begins growing jealous and temperamental, feeling dejected and hopeless and ready to return to San Francisco. Sestero’s auditions also dry up. He shares his frustrations with Wiseau, wishing that he could simply make a movie to supply himself with a role. Wiseau takes this suggestion literally.
Over the next three years, Wiseau writes The Room, and presents it to Sestero. Despite recognizing its incoherence, Sestero insists to Wiseau that the script is great. Wiseau offers him the role of Mark, along with an associate producer credit. Sestero reluctantly accepts. They rent out Birns & Sawyer, a production house in North Hollywood. Wiseau insists on buying all of the production equipment himself, as well as insisting that the film be shot on 35mm film and HD Digital simultaneously. The employees of Birns & Sawyer introduce Wiseau to Raphael Smadja and Sandy Schklair, who work as his cinematographer and script supervisor respectively. Schklair, however, essentially performs all the director responsibilities for Wiseau. Production initially starts out smooth, but Wiseau grows increasingly narcissistic and demanding. He verbally lashes out at crew members, repeatedly forgets his lines, shows up late nearly every day, and refuses to supply his crew with basic needs such as drinking water. This culminates in Carolyn Minnott (who plays Claudette) fainting from exhaustion.
The crew grows more resentful of Wiseau, with many questioning his behavior despite an endless supply of money that nobody knows the source of. During prep for a sex scene, Wiseau humiliates Juliette Danielle (who plays Lisa) by pointing out how “disgusting” her body acne is in front of the entire crew. Smadja reaches his limit, and Wiseau briefly fires him. Having filmed near-constant behind-the-scenes footage, Wiseau reveals that he knows everybody hates him, and believes that nobody, including Sestero, is interested in seeing his vision through. One afternoon, Sestero and Amber happen upon Malcolm in the Middle star Bryan Cranston, who invites the bearded Sestero to fill in for a small lumberjack part in a Malcolm episode currently shooting. Sestero begs Wiseau to postpone shooting his beard-free scenes by a day to accommodate Cranston’s opportunity, but Wiseau refuses, disillusioning Sestero even further and causing Amber to split up with him. On the last day of shooting, Sestero finally calls Wiseau out for being entitled and selfish throughout the course of their friendship, and questioning his age, background, and source of income. They get into a brief physical altercation and do not see each other for eight months.
Eventually, Wiseau invites Sestero to the premiere of The Room. To Sestero’s surprise, Schklair, Smadja, and the entire cast and crew attend. Wiseau introduces the film, and as it goes on, the entire audience gradually erupts in laughter over the horribly made movie. Wiseau walks out of the theater, upset with this reaction, but Sestero comforts him, telling him that while it may not have been the response he hoped to receive, they’ve never seen an audience have a better time at the movies. With this bit of perspective, Wiseau returns to the front of the theater as the credits roll, takes credit for his “comedic” movie, and receives a standing ovation from the audience.
Real-life clips of Wiseau attending screenings of The Room play, and title cards explain that the film made $1,800 against its reported $6 million budget during its initial release (Wiseau kept it running for two weeks, allegedly to qualify for the Academy Awards), but it has since become a profitable cult film. Wiseau and Sestero remain friends, and to this day, Wiseau’s age, past life and source of income remain a mystery. Scenes from The Room are then compared side-by-side with reenactments of the scenes performed by The Disaster Artist’s cast.
In a post-credits scene, Wiseau has an odd verbal exchange with Henry (played by the real Tommy Wiseau), who offers to hang out, but Wiseau refuses.