Producer Lauren Shuler Donner first thought of a prequel based on the young X-Men during the production of X2, and later producer Simon Kinberg suggested to 20th Century Fox an adaptation of the comic series X-Men: First Class, though the film does not follow the comic closely. Bryan Singer, who had directed both X-Men and X2, became involved with the project in 2009, but he had to only produce and co-write First Class due to other projects. Matthew Vaughn, who was previously attached to both X-Men: The Last Stand and Thor, became the director, and also wrote the final script with his writing partner Jane Goldman. While First Class wound up overtaking a planned Magneto prequel that entered development hell and the Writer's Guild of America arbitration gave a story credit to Magneto writer Sheldon Turner, Turner's script was not read by any of the First Class screenwriters.
First Class entered production in August 2010, with principal photography concluding in December and additional filming finishing in April 2011, just a few weeks before the film's premiere in June 2011. The tight schedule proved a challenge to the six companies responsible for the extensive visual effects, which included computer-generated sets and digital doubles for the actors. Locations included Oxford, the Mojave desert and Georgia, with soundstage work done in both Pinewood Studios and the 20th Century Fox stages in Los Angeles. The depiction of the 1960s drew inspiration from the James Bond films of the period. First Class received positive reviews, being considered a well-written and fresh revival of the franchise, and was a box-office success with earnings of $353 million worldwide. A sequel titled X-Men: Days of Future Past, also serving as a sequel to X-Men: The Last Stand and a follow up to The Wolverine, was released in May 2014, with First Class producer Bryan Singer returning as director after X-Men and X2 and Vaughn acting as co-writer.
In a German camp in occupied Poland during World War II in 1944, Nazi Germany scientist Dr. Klaus Schmidt observes young Erik Lensherr telekinetically bend a metal gate when the child is separated from his mother. Meanwhile, at a mansion in Westchester County, New York, child telepath Charles Xavier meets young shapeshifter Raven Darkholme, whose natural form is blue-skinned and scaly. Overjoyed to meet someone else "different", he invites her to live with his family as his foster sister. In his office in Germany, Schmidt orders Lensherr to move a coin on a desk, and kills the boy's mother when Lensherr cannot. In grief and anger, Lensherr's magnetic power manifests, killing two guards and destroying the room.
In 1962, Lensherr is tracking down Schmidt while Xavier is graduating from the University of Oxford with a thesis about mutation. In Las Vegas, Central Intelligence Agency officer Moira MacTaggert follows U.S. Army Colonel Hendry into the Hellfire Club, where she sees Schmidt (now known as Sebastian Shaw), with mutant telepath Emma Frost who can also turn her body to diamond, cyclone-producing Riptide, and demonic-appearing teleporter Azazel. Threatened by Shaw and teleported by Azazel to the Joint War Room, Hendry advocates deployment of nuclear missiles in Turkey. Shaw, an energy-absorbing mutant, later kills Hendry.
MacTaggert, seeking Xavier's advice on mutation, takes him and Raven to the CIA, where they convince Director John McCone that mutants exist and that Shaw is a threat. Another CIA officer sponsors the mutants and invites them to the secret "Division X" facility. MacTaggert and Xavier find Shaw as Lensherr is attacking him, and rescue Lensherr from drowning as Shaw escapes. Xavier brings Lensherr to Division X, where they meet young scientist Hank McCoy, a mutant with prehensile feet, who believes Raven's DNA may provide a "cure" for their appearance. Upon hearing this, Raven voluntarily provides McCoy with a blood sample. Xavier uses McCoy's mutant-locating device Cerebro to seek recruits against Shaw. Xavier and Lensherr recruit stripper Angel Salvadore. Later, taxi driver Armando Muñoz, Army prisoner Alex Summers, and Sean Cassidy join, and code-name themselves Darwin, Havok, and Banshee, respectively. Raven dubs herself Mystique.
Xavier, MacTaggert and Lensherr track down Frost, who is meeting with a Soviet general in the USSR. Lensherr enters the premises, hoping to locate Shaw and kill him, with Xavier closely following. They instead encounter Frost, who they capture and unveil Shaw's intentions to start World War III and trigger mutant ascendency. Meanwhile, Azazel, Riptide, and Shaw attack Division X, killing everyone but the mutants, and invite them to join him. Angel accepts; when Havok and Darwin retaliate, Shaw absorbs Havok's energy blast and uses it to kill Darwin.
Torn by the death of their new companion, the mutants decide to avenge Darwin, and Xavier takes them to his family mansion for training. In Moscow, Shaw compels the general to have the USSR install missiles in Cuba. Wearing a helmet that foils Xavier's telepathy, Shaw shadows the Soviet fleet in a submarine to ensure the missiles break a U.S. blockade.
Later, McCoy visits Raven with the completed 'cure' for their appearance. Raven, thinking McCoy approves her natural form, tells him not to use the cure. When she later attempts to seduce Lensherr by making herself look older, Lensherr instead tells her she is beautiful in her blue mutant form. McCoy uses the cure on himself but it backfires, giving him blue fur and leonine aspects. With McCoy piloting, the mutants and MacTaggert take a jet to the blockade line, where Lensherr uses his magnetic power to lift Shaw's submarine from the water and deposit it on land. During the ensuing battle, Lensherr seizes Shaw's helmet, allowing Xavier to immobilize Shaw. Lensherr tells Shaw he shares Shaw's exclusivist view of mutants but, to avenge his mother, kills Shaw — over Xavier's objections — by forcing the Nazi coin of his youth through Shaw's brain.
Fearing the mutants, both fleets fire missiles at them, which Lensherr turns back in mid-flight as Xavier tries to stop him, allowing some of the missiles to explode before reaching the fleets. MacTaggert tries to stop Lensherr by shooting him but he deflects the bullets, one of which hits Xavier in the spine, and another of which hits Raven in the navel. Lensherr rushes to help Xavier and, distracted, allows the remaining missiles to fall into the ocean. Xavier informs Lensherr that they have contradicting opinions for mutants, and a hurt Lensherr leaves with Angel, Riptide, Azazel, and Mystique. Later, Xavier, who is now wheelchair bound, expresses his intentions to transform his mansion into a school for mutants. MacTaggert, who supports the idea, promises never to reveal his location and they kiss; at a CIA debriefing later, she says she has no clear memory of recent events. Lensherr, now calling himself "Magneto", frees Frost from confinement.
- James McAvoy as Charles Xavier / Professor X:
- The telepathic leader and founder of the X-Men. He is a close friend of Erik Lensherr until their differing views of mutantkind's place in humanity create a schism between them.
- McAvoy was Vaughn's top choice for Xavier, and, after being cast, auditioned with every actor considered for Magneto to test the duo's chemistry. McAvoy said he did not read comic books as a child, but added that he was a fan of the X-Men cartoons from the age of 10. While he describes the older Charles Xavier as "a monk... a selfless, egoless almost sexless force for the betterment of humanity and mortality", he says that the younger Xavier is a very different person. "It's quite fun because the complete opposite of that is an ego-fueled, sexed up self-serving dude. And not going too far with it, but he's definitely got an ego and he's definitely got a sex drive as well." McAvoy admitted to feeling similarities between Xavier/Magneto and Martin Luther King Jr./Malcolm X stating that the film was "sort of like meeting them at a point where they are still finding out who they are and you are still seeing some of the events that shaped them." McAvoy avoided doing any callbacks to Patrick Stewart's performance as Xavier as Vaughn told him and Michael Fassbender to only take the allusion to Xavier and Magneto's old friendship in the other movies as inspiration. Vaughn stated that since he considered that Professor X was "a bit of a pious, sanctimonious boring character, and he's got too much fucking power", the script would make young Xavier more interesting by "making him more of a rogue" who would become more responsible as his mission of finding more mutants went on.
- Laurence Belcher played the 12-year-old Charles Xavier.
- Michael Fassbender as Erik Lensherr / Magneto:
- A mutant capable of manipulating and generating electromagnetic fields. He becomes Xavier's friend and ally until their philosophical differences create a schism between them.
- Fassbender had auditioned for an earlier Matthew Vaughn project, and the director had remembered him and sent Fassbender the X-Men script. Though Fassbender knew little of the superhero team, he became interested in the part after reading the script and familiarizing himself with Magneto in the comic books. Fassbender, who saw Lensherr as a Machiavellian character who is neither good nor evil, watched Sir Ian McKellen's performances to get the flavor of Magneto, but ultimately chose to "paint a new canvas" with the character, "just going my own way and working with whatever is in the comic books and the script." Vaughn said Lensherr "is straight up cool; he's Han Solo while Professor X is Obi-Wan Kenobi".
- Bill Milner plays the young Erik Lensherr.
- Kevin Bacon as Dr. Klaus Schmidt / Sebastian Shaw:
- A former Nazi scientist and the leader of the Hellfire Club, a secret society bent on taking over the world. He has the power of absorbing and redirecting kinetic and radiated energy.
- Producer Lauren Shuler Donner said Bacon was considered for Shaw for being an actor who could convey a villain "with different shades, that's not always clear that he's the bad guy". Vaughn added that Bacon "had that bravado that Shaw needed", while stating that the actor was his top choice along with Colin Firth. Bacon accepted the role as he was a fan of Vaughn's Kick-Ass, and liked both the character of Shaw and the script, which he described as "a fresh look at the franchise, but also the comic book movies in general". The actor considered that Shaw was a sociopath to whom "the morality of the world did not apply", with producer Simon Kinberg adding that Bacon portrayed him as "somebody, who in his mind, is the hero of the movie". Bacon also said that "aside from the kind of evil side, I portrayed him as kind of a Hugh Hefner type".> Vaughn discarded Shaw's look from the comics as he felt he would "look like an Austin Powers villain".
- Rose Byrne as Moira MacTaggert:
- A CIA agent who befriends Xavier and Lensherr.
- Byrne said she was unfamiliar with both the comics and the film series, except for "what a juggernaut of a film it was". The actress was cast late into production, which had already begun by the time she was picked for the role. MacTaggert was described by Byrne as "a woman in a man’s world, she’s very feisty and ambitious—you know, she’s got a toughness about her which I liked".
- Jennifer Lawrence as Raven Darkholme / Mystique:
- A shape-shifting mutant and Charles Xavier's childhood friend/ adoptive sister.
- After the dramatic Winter's Bone, Lawrence sought First Class to do "something a little lighter". Vaughn said Lawrence was picked because "she could pull off the challenging dichotomy that Raven faces as she transforms into Mystique; that vulnerability that shields a powerful inner strength." Lawrence had some reservations about her performance due to Mystique's previous portrayal by Rebecca Romijn, as she considered Romijn to be "the most gorgeous person in the world", and felt their portrayals were very contrasting, feeling hers was "sweet and naive" while Romijn was "sultry and mean". The actress went on a diet and had to work out for two hours daily to keep in shape, and for Mystique's blue form, Lawrence had to undergo an eight-hour make-up process similar to that of Romijn on the other films. The first day with make-up even caused blisters to appear on Lawrence's upper body. Lawrence reported that she was still finding traces of blue paint inside her belly button two weeks after filming had wrapped up.
- Morgan Lily plays the young Raven—with the actress wearing a slip-on bodysuit and facial appliances which only took one hour and a half to apply, as subjecting a child actor to the extensive make-up was impractical—and Romijn herself has a brief uncredited cameo as an adult Mystique, which Vaughn added as an in-joke—the script has Raven "becom[ing] Brigitte Bardot or Marilyn Monroe, like an older sex icon of those times".
- January Jones as Emma Frost:
- An extremely strong telepath who can also change her entire body into hard diamond form which grants her superhuman strength, durability, agility, stamina, dexterity, and endurance. Unfortunately, it prevents her from using her telepathic abilities. She is a member of the Hellfire Club.
- Prior to Jones' casting, Alice Eve was the subject of what Variety called "widespread Internet reports" that Eve "was set to play Emma Frost, although no deal was in place." Jones accepted the role to get something different from her job in the TV series Mad Men. While discovering that like the show First Class was set in the 1960s, the actress considered that "[Frost]'s so, so far from Betty and from Mad Men, and it takes place in that time but it doesn’t feel like a period movie." The actress described the revealing costumes of the character as "insane," saying, "She's got quite the bod, which is very intimidating". The actress stated that she did only a limited exercise routine to keep in shape, as "I'm a petite person, so I didn't want to go into a strict workout and eating regime."
- Nicholas Hoult as Dr. Hank McCoy / Beast:
- A genius scientist who has mutant abilities similar to those of the great apes. He attempts to cure himself of what he believes to be physically debilitating aspects of his mutation only to be is transformed into a frightening-looking blue-furred apeman. Despite his new appearance, he is kind and caring at heart.
- Broadway actor Benjamin Walker was previously cast as Beast, but eventually turned down the role to star in the Broadway musical Bloody Bloody Andrew Jackson. Hoult was chosen for being "gentle with a capability of being fierce", and admitted to being both an X-Men fan and enthusiastic on both returning to the action genre aften 2010's Clash of the Titans and working with the film's cast. The actor had to use makeup that took four hours to apply when Hank becomes the Beast, which include a mask, contact lenses, a furry muscle suit and fake teeth. As Vaughn wanted Beast to look more feral than the version Kelsey Grammer played in X-Men: The Last Stand, the redesign went through various tests, which tried to make Beast not resemble any particular animal but still look like Hoult, as well as with a furry body, which makeup artist Alec Gillis of Amalgamated Dynamics likened to "something akin to a wolf's pelt on his face, his arms-everywhere". The suits employed actual dyed fur from fox pelts.
- Oliver Platt as Man In Black Suit:
- A CIA agent and head of Division X, a government agency working with the X-Men. Vaughn had considered his friend Dexter Fletcher for the part, but the studio felt the cast had too many British actors, and Fletcher himself declined, to direct Wild Bill.
- Ray Wise as the United States Secretary of State.
- Vaughn stated he cast Platt and Wise in minor parts because "I think people with one line are just as important as someone with a thousand lines. It takes one bad delivery to remind the audience that they're watching a film. So, if I can get away with casting great actors in smaller roles, I'll take it."
- Zoë Kravitz as Angel Salvadore:
- A mutant with dragonfly wings and acidic saliva.
- The make-up team took four hours to apply Angel's wing tattoo on Kravitz, and the visual effects team had to erase the tattoo in case the scene required Angel with the computer-generated wings. To depict flight, Kravitz stood on elevated platforms and was dangled on wires, at times from a helicopter to allow for varied camera angles.
- Caleb Landry Jones as Sean Cassidy / Banshee:
- A mutant capable of emitting incredibly strong ultrasonic screams, sonic blasts, sonic bursts, and sonic waves used in various ways including as a means of flight.
- Jones auditioned without knowing what X-Men character he was up for, saying he auditioned because it was a superhero that fit his biotype: "I've got red hair and freckles, I'm not gonna be Batman, Robin or Spider-Man". The actor also stated that the script defined the character more than the comics, as Banshee went through various reinventions in print. Given Banshee gets involved with MacTaggert in the comics, Jones also tried to "look at her just a little bit differently, you know, when I can." As Jones suffers from acrophobia, using the rig that was to depict Banshee's flight required much preparation time with the stunt team.
- Lucas Till as Alex Summers / Havok:
- A mutant who has the ability to absorb energy and discharge it as blasts. The producers told Till his audition served for both Havok and Beast, and the actor replied that despite his lifelong dream of playing a superhero, "I know you'll kill me, but if I get Beast, I'm not in the movie. I'm not going through that makeup every day."
- Edi Gathegi as Armando Muñoz / Darwin:
- A mutant with the ability of "reactive evolution."
- Gathegi became interested in a role in the X-Men films after seeing X2, and had previously auditioned for Agent Zero in X-Men Origins: Wolverine. He read for Banshee while auditioning for First Class, and only learned he was playing Darwin a few days prior to the shoot. Gathegi worked out and entered an eating regime to get in shape, and also researched the comics about his character. All of Darwin's transformations—getting gills, turning his skin into concrete—were done through computer graphics, with a computer-generated version of Gathegi that could seamlessly blend in and out of the human form.
- Jason Flemyng as Azazel:
- A mutant who has the ability to teleport, and is also a member of the Hellfire Club.
- Flemyng, who had previously been considered for Beast in The Last Stand, said he did not want more make-up heavy roles after playing Calibos in Clash of the Titans, but made an exception for Azazel as he liked working with Vaughn. Due to the Cold War setting, Flemyng tried to imply that Azazel is Russian to partly explain his pleasure in killing CIA agents. The actor spent eight weeks with fight training, particularly with swords, and had to undergo a four-hour make-up process, which like Mystique was designed by Spectral Motion—but did not include Azazel's tail, which was computer-generated. Shuler Donner considered that the problems with the shade of red on Azazel's skin - "some looked like the Devil, some like a man wearing red paint" - was overcome by adding scars that made him more human, eyes brighter than Flemyng's own, and "a black mane of hair that seemed to tie everything in".
- Álex González as Janos Quested / Riptide:
- A mutant with the ability to create powerful whirlwinds from his hands and body.
- First Class marks the first English-language film for González, who auditioned while taking English classes in London. He enjoyed playing a villain as most of his film roles in Spain were for "good guys", and compared Riptide's respectable and polite personality, which can suddenly be dropped to perform fierce attacks, to a hurricane; in a translation of a Portuguese-language interview, he is quoted as saying, "When I see a hurricane from far, it is calm. The only thing I can see is a kind of tube. But from inside, up close, it is really dangerous."
- Glenn Morshower as Colonel Hendry
- Matt Craven as CIA Director McCone
- Rade Šerbedžija as Russian General
- Michael Ironside as a U.S. Navy Captain
- James Remar as a U.S. General
- Annabelle Wallis as Amy:
- A young woman Xavier flirts with in a bar, after observing she has heterochromia.
- Don Creech as Agent Stryker:
- A CIA Agent who is the father of Colonel William Stryker, from X2, X-Men: Days of Future Past, and X-Men Origins: Wolverine.
Hugh Jackman reprises his role as Wolverine in an uncredited cameo in a bar, dismissing an approach by Xavier and Lensherr to join them. Jackman said he accepted the offer to appear because "it sounded perfect to me", particularly for Wolverine being the only character with a swear word. The cameo took about eight takes during a two-hour shoot on the Fox Studios lot in Los Angeles, and the actor changed his line in an ad-lib from "Fuck off" to "Go fuck yourself". X-Men creator Stan Lee, who appeared in the first three movies and regularly cameos in other Marvel-based movies, explained that he was unable to participate in First Class because "they shot it too far away".
A young Storm makes a cameo appearance while Professor X is tracking mutants using Cerebro.