On the evening of May 12, 1956, while filming Raintree County, Clift was involved in a serious auto accident when he apparently fell asleep while driving and smashed his car into a telephone pole minutes after leaving a dinner party at the Beverly Hills home of his Raintree County co-star and close friend Elizabeth Taylor and her second husband, Michael Wilding. Alerted by friend Kevin McCarthy, who witnessed the accident, Taylor raced to Clift's side, manually pulling a tooth out of his tongue as he had begun to choke on it. He suffered a broken jaw and nose, a fractured sinus, and several facial lacerations which required plastic surgery. In a filmed interview, he later described how his nose could be snapped back into place.
After a two-month recovery, he returned to the set to finish the film. Against the movie studio's worries over profits, Clift correctly predicted the film would do well, if only because moviegoers would flock to see the difference in his facial appearance before and after the accident. Although the results of Clift's plastic surgeries were remarkable for the time, there were noticeable differences in his appearance, particularly the right side of his face. The pain of the accident led him to rely on alcohol and pills for relief, as he had done after an earlier bout with dysentery left him with chronic intestinal problems. As a result, Clift's health and physical appearance deteriorated considerably from then until his death.
Acting teacher Robert Lewis called Clift’s subsequent career “the longest suicide in Hollywood history” – an unfair summary, since his work in the ten remaining years of his life included a haunting performance in The Misfits opposite Marilyn Monroe who famously described him as “the only person I know who is in even worse shape than I am". He worked with Taylor again in Suddenly, Last Summer (1959) and starred as Sigmund Freud in John Huston’s Freud (1962). But his self-destructive qualities made him increasingly unemployable, despite loyal support from friends and admirers.
On July 22, 1966, Clift spent most of the hot summer day in his bedroom in his New York City townhouse, located at 217 East 61st Street. He and his live-in personal secretary, Lorenzo James, had not spoken much all day. Shortly before 1:00 a.m., James went up to say goodnight to Clift, who was still awake and sitting up in his bed. James asked Clift if he needed anything and Clift politely refused and then told James that he would stay up for a while either to read a book or watch some television. James then noted that The Misfits was on television that night airing as a late-night movie, and he asked Clift if he wanted to watch it with him. "Absolutely not!" was the firm reply. This was the last time Montgomery Clift spoke to anyone. James went to his own bedroom to sleep without saying another word to Clift. At 6:30 a.m. the next day, James woke up and went to wake Clift, but found the bedroom door closed and locked. James became more concerned when Clift did not respond to his knocking on the door. Unable to break the door down, James ran down to the back garden and climbed up a ladder to enter through the second-floor bedroom window. Inside, he found Clift dead: he was undressed, lying on his back in bed, with eyeglasses on and both fists clenched by his side. Clift was age 45 when he died. James then used the bedroom telephone to call the police and an ambulance.
Clift's body was taken to the city morgue less than two miles away at 520 First Avenue and autopsied. The autopsy report cited the cause of death as a heart attack brought on by "occlusive coronary artery disease". No evidence was found that suggested foul play or suicide. It is commonly believed that drug addiction was responsible for Clift's many health problems and his death. In addition to lingering effects of dysentery and chronic colitis, an underactive thyroid was later revealed during the autopsy. The condition (among other things) lowers blood pressure; it may have caused Clift to appear drunk or drugged when he was sober and also raises cholesterol, which may have contributed to his heart disease.
Following a 15-minute ceremony at St. James' Church attended by 150 guests, including Lauren Bacall, Frank Sinatra and Nancy Walker, Clift was buried in the Friends [Quaker] Cemetery, Prospect Park, Brooklyn, New York City. Elizabeth Taylor, who was in Rome, sent flowers, as did Roddy McDowall, Myrna Loy and Lew Wasserman...