The film begins with a mock newsreel sequence showing the chaos around the death of 31-year-old film star Rudolph Valentino (Rudolph Nureyev). Thousands of fans mob the funeral home until order is restored, at which point the important women in Valentino's life come to mourn. Each remembers him via flashbacks.
The first of these women Bianca de Saulles (Emily Bolton) who knew Valentino when he was a taxi dancer, and gigolo in New York City. He shares with her his dream of owning an orange grove in California. After mobsters rob him, he decides he must make the move west.
Next is a young movie executive and screenwriter named June Mathis (Felicity Kendal), who has an unrequited love for Valentino. She first meets Valentino in California, where he upsets Mr. Fatty (William Hootkins) by grabbing the starlet next to Arbuckle and romancing her into becoming his first wife, Jean Acker (Carol Kane). Acker's glamorous and luxurious life, made possible by acting in movies, motivates Valentino to try acting himself. Mathis recalls seeing him in a bit part in a movie and, based on that alone, recommending him for a larger role in her next project, The Four Horsemen of the Apocalypse. The hugely successful 1921 film launches Valentino to superstardom, and she is proud to have discovered him.
Back at the funeral, Alla Nazimova (Leslie Caron) makes a flamboyant entrance. She proceeds to make a scene and, when the photographers ask her to repeat it for the cameras, she obliges. Nazimova claims a relationship with Valentino and recalls working on Camille with him.
Next Natacha Rambova (Michelle Phillips) enters and tells reporters that, even though she and Valentino are physically separated, they are still close via the spirit world. Her flashback shows that she was at first Nazimova's lover, but that, realizing Valentino's star would far outweigh Nazimova's, she decided to take advantage of Valentino's infatuation with her to do some social climbing. During the filming of The Sheik, she seduces Valentino with a seven veils dance. Despite knowing he is in the midst of divorcing Acker, she insists on going to Mexico so they can marry. Once they return to the states, Valentino is arrested for bigamy. Because Jesse Lasky (Huntz Hall) refuses to pay bail for Valentino, he has to spend the night in jail, where the guards deny him bathroom privileges and, with the other prisoners, taunt him about his lack of masculinity. The result is his complete humiliation.
On the set of Monsieur Beaucaire, Rambova and Sidney Olcott (John Justin) take over directing. Two stage hands, wondering if 'Rambova calls the shots in bed, too', toss a pink powder puff onto Valentino's lap. Rambova demands that whoever did it come forward or she and Valentino will walk off the set for good. Valentino finishes the picture, but Rambova insists he refuse future work at Paramount until Lasky meets certain demands. Lasky suspends them and they end up broke. A man named George Melford (Seymour Cassel) approaches them; Melford is meant to be Valentino's real-life manager, George Ullman. He offers to help them book personal appearances for Mineralava, a beauty product company. The tour is a success, and, with Melford's help, Valentino and Rambova negotiate a good deal with Lasky.
A dramatic moment comes when Valentino reads a newspaper article questioning his manhood. Earlier, the film shows Valentino dancing with the young Vaslav Nijinsky (Anthony Dowell) in a way that casts doubt on Valentino's sexuality. Whatever his true attractions are, the article outrages Valentino, who challenges the reporter to a duel. For 'legal reasons' the duel becomes a boxing match. Rory O'Neil (Peter Vaughn), who just happens to be a professional boxer, stands in for the reporter. The fight becomes a ballet of sorts, and flashbacks to the dance with Nijinsky parallel the match. Valentino eventually lands a blow which wins him the fight. However, he now begins to exhibit signs of an ulcer.
O'Neil asks for a rematch, this time a drinking contest. Despite his ulcer, Valentino accepts. Although Valentino defeats O'Neil again, his excessive drinking is too much for the ulcer, which perforates when he returns to his home that night. He dies crawling on the floor unable to reach an orange he had drunkenly played with and dropped on the floor (representing his failed dream of growing an orange grove) The film ends with a shot of Valentino's body on a slab in a mortuary as the credits roll.
The film topped the British box-office for two weeks, but was not a hit in America.
Upon its release there, Valentino was a commercial and critical failure. The film garnered mixed reviews, most generally negative. The Village Voice called the film "so embarrassingly and extensively bad that it achieves a kind of excruciating consistency with the rest of his [Russell's] career." Charles Champlin of The Los Angeles Times dismissed the film as "superficial and silly". Although Gene Siskel of the Chicago Tribune gave a three-star rating to the film, sensing that it was an example of a critique of Hollywood, he noted that it suffered from what he felt was Russell's apparent dislike and disregard for Valentino.
The majority of the negative criticism stemmed from Russell's blending of fact and fiction. Russell defended his actions stating, "I only want to be accurate up to a point. I can be as inaccurate as I want—it makes no difference to me. I'm writing a novel. My films are novels, based on a person's life, and a novel has a point of view."
Despite its general negative reception, some critics and scholars liked and respected the film. Russell later stated that he would rather forget Valentino.
The film was later included in John J. B. Wilson's 2005 book The Official Razzie Movie Guide.