By 1925 he was MGM's biggest male star; his films were very profitable for the studio. Cultivated as a romantic leading man, his good looks and flair for comedy won him many fans. He made a career out of playing wise-cracking young athletic types whose large egos held them back until an attitude adjustment brought success.
Haines was openly homosexual. From 1926, Haines lived with Jimmy Shields, whom he had met when Shields was his stand-in for a film. Studio publicists were able to keep Haines' sexual orientation from the press. However, in 1933, Haines was arrested in a YMCA with a sailor.
Louis B Mayer, head of MGM, gave him an ultimatum: choose between a sham marriage or his relationship with Shields. To his credit, Haines chose Shields and they were ultimately together for 50 years. Mayer fired him and terminated his contract.
Haines did make a few minor films at Poverty Row studios, then retired from film. His final films were made with Mascot Pictures, Young and Beautiful and The Marines Are Coming in 1934.
Haines and Shields began a successful career as interior designers and antique dealers. Some of their early clients were friends like Joan Crawford, Gloria Swanson, Carole Lombard and George Cukor.
Their lives were disrupted in 1936 when members of the Ku Klux Klan dragged them from their home and beat them, because a neighbour accused them of propositioning his son. Crawford, and other stars, urged the men to report this to the police. Marion Davies asked her lover William Randolph Hearst to use his influence to ensure the neighbours were prosecuted to the full extent of the law, but ultimately Haines and Shields chose not to report the incident.
The couple finally settled into the Hollywood community in Malibu, and their business prospered until their retirement in the early 1970s, except for a brief interruption when Haines served in World War II. Their long list of clients included Ronald and Nancy Reagan when Reagan was governor of California.
Haines never returned to films. Gloria Swanson (a lifelong friend) personally invited him a to appear with her in Sunset Boulevard (1950) but he declined.
Haines and Shields remained together for the rest of their lives. Joan Crawford described them as "the happiest married couple in Hollywood". Haines died from lung cancer at the age of 73. Soon afterward, Shields, who suffered from what many believe to be Alzheimer's Disease, put on Haines' pyjamas, took an overdose of pills, and crawled into their bed to die. They were interred side by side in the Woodlawn Memorial Cemetery.
William Haines has a star on the Hollywood Walk of Fame at 7012 Hollywood Boulevard. His life was detailed in William J Mann's 1998 biography, Wisecracker: The Life and Times of William Haines, Hollywood's First Openly Gay Star.