The movie was directed by Bryan Singer and explores the ideas of prejudice and discrimination in the United States. The screenplay was written by David Hayter (who has a cameo appearance in the film as a police officer in the Statue of Liberty area). A sequel, X2: X-Men United, was released in 2003 and a third film, X-Men: The Last Stand, was released in 2006. The film franchise also brought up interest in a Wolverine-centered film and a Magneto-centered film.
According to Joss Whedon, who made an early draft of the screenplay, only two parts of his draft made it into the final film. The first is the exchange between Wolverine and Cyclops ("It's me." "Prove it!" "You're a dick."); the other is Storm's, "Do you know what happens to a toad when it's struck by lightning? The same thing that happens to everything else." Whedon was disappointed with Halle Berry's over-dramatic delivery of the latter line, which he imagined as an offhand, casual comment.
Wolverine's claws required a full silicone cast of Hugh Jackman's arm, and 700 versions for Jackman and his stunt doubles.
The scene at the train station where the young boy smiles at Cyclops, and Cyclops smiles back was unplanned. The boy was a huge fan of the X-Men, and Cyclops was his favorite. The scene originally called for Cyclops to look at the train schedule, however, according to Bryan Singer, the boy could not stop smiling at James Marsden (the actor playing Cyclops). Finally, during one shot, Marsden just looked back at him and smiled, much to the boy's delight. Bryan Singer liked the idea so much, he kept it in the film, and told the actress playing the boy's mother to react the way she did.
The relatively unspectacular scene where the X-Men leave the X-Jet and hop over a wall to step into the Statue of Liberty caused much hilarity. The reason was that the actors Berry, Janssen, Marsden and Jackman wore such tight fitting costumes that they simply could not make the jump over the small ledge. Another problem was that they were supposed to hold their breath to avoid clouding in the cold weather, a point which Berry forgot at least once. This can be all seen on the blooper reel of the DVD X-Men 1.5.
During the film, as Logan mocks the X-Men's black uniforms, Cyclops replies: "What would you prefer? Yellow spandex?" This is a reference to Wolverine's blue-and-yellow uniform from the comics.
At one point in the film, Toad grabs an iron pole and proceeds to twirl it around in a fashion not unlike that of Gambit. In actual fact this was in reference to the Star Wars character Darth Maul, whom actor Park had portrayed in Star Wars Episode I: The Phantom Menace.
When appearing at Wondercon 2006 to promote Superman Returns (2006), Bryan Singer mentioned that he originally approached composer John Williams to compose the score for X-Men, but Williams was too busy composing the score for Saving Private Ryan (1998).
In the scene when Senator Kelly emerges from the water at the beach a hot dog vendor that can be seen. The vendor is Stan Lee, the original creator of X-Men. George Buza, the voice of Beast in the X-Men animated series, has a cameo as the truck driver who brought Anna Paquin's Rogue to the bar at the beginning of the film.
Much of the film was shot at locations in and around Toronto, Ontario. Casa Loma, a local landmark and museum, was used as the set for all above-ground scenes inside Xavier's school. The scenes in Cerebro were filmed in a large soundstage within the downtown CBC building. Hamilton's Liuna Station, a former train station converted into an event hall, stood in for the Westchester train station in the unavailability of Toronto's downtown Union Station. A beach in nearby Oakville was originally intended to serve as the beach where Senator Kelly washes up after his escape from Magneto.
During filming of the scene just outside the train station, Bryan Singer was prevented entry by a local police officer, who was assisting with crowd control. Singer's youthfull appearance and casual dress failed to impress the officer, who flatly refused to believe that the "kid" in front of him was even involved in the film, let alone somebody important.
The film went on to become one of the biggest hits of 2000, taking in more than $296 million worldwide and becoming the 8th highest grossing film, domestically, of that year. The film is also widely credited as being the patriarch of the current "Comic Book Movie Age" that Hollywood is currently experiencing with releases such as, Spider-Man, Spider-Man 2, Spider-Man 3, Daredevil, Fantastic Four, The Punisher, Constantine, Sin City, Batman Begins, V for Vendetta, The Hulk, Superman Returns, Ghost Rider, X2: X-Men United and X-Men: The Last Stand.
Some fans were not entirely pleased with the first large scale adaptation of the X-Men. Many fans complained about the change in costumes and the overall depiction of Rogue as frightened, naive, and defenseless - even with her powers. Another overall complaint was that the other X-Men, featured so prominently in the comic books, were relegated to playing second fiddle against Wolverine. Many fans felt that Cyclops in particular, the field leader of the X-Men, and his long-term romance with Jean Grey were minimalized to emphasize Wolverine's role in the group, and Wolverine's infatuation with Jean.