James McAvoy as Professor X
Comic Bio: Charles Xavier’s dream is Mutants and Humans live together in harmony and as equals. His friend the mutant known as Magneto does not believe this is possible. Professor used his family's fortune to build a school for the mutant community, where he could teach them to use their powers safely and with responsibility.
For his dream to come true he needs to fight for it enters his team of X-Men, named not from Xavier's moniker, but for the gene in Mutant DNA that gives them their powers. Alongside his X-Men, he strives to defend and protect the humans that would otherwise be targets of more violent factions of mutant-kind.
Born with psychic abilities, he is arguably the most powerful telepath on the planet.
Previous CBM incarnation:
Sir Patrick Stewart in X-Men, X2: X-Men United, X-Men: The Last Stand and CGI’d Stewart in X-Men Origins: Wolverine
Michael Fassbender as Magneto
Comic Bio: Magneto is a powerful mutant with the ability to generate and control magnetism, He has been the X-Men's most prominent enemy ever since his first appearance. In his early appearances, his motives were bent on megalomania, but writers have since fleshed out his character and origin, revealing him to be a Jewish Holocaust survivor whose actions are driven by the purpose of protecting the mutant race from suffering a similar fate. His role in comics have varied from supervillain to antihero to even hero.
Previous CBM incarnation:
Sir Ian McKellen in X-Men, X2: X-Men United, X-Men: The Last Stand
Kevin Bacon as Sebastian Shaw
Comic Bio: Sebastian Shaw is a mutant that possesses the ability to absorb kinetic energy and transform it into raw strength. He is the leader of the New York branch of the Hellfire Club, a secret society bent on world domination, although to the public, he is a legitimate businessman and ordinary human. He once funded the mutant-hunting Sentinel program to keep it under his thumb.
X-Men First Class will be Sebastian Shaw’s first adaptation to live media.
January Jones as Emma Frost
Comic Bio: Emma Frost is an urbane, mutant telepath with a well-noted dry wit she was formerly known as the White Queen. In the comics Frost has changed from one of the X-Men's most dangerous foes to one of its most central members.
Previous CBM/TV incarnation
Finola Hughes portrayed Emma Frost in a 1996 TV movie titled Generation X.
Tahyna Tozzi portrayed Emma/Kayla Silverfox’s sister in X-Men Origins: Wolverine. The character showcased the ability of turning her skin into diamond a later mutation by the comicbook version of Emma Frost, note that this version of Emma did not display any telepathic powers. It remains to be seen if this Emma is one and the same with the Jones’ version, or related to the character.
Rose Byrne as Moira MacTaggert
Comic Bio: Dr. Moira MacTaggert is the daughter of the powerful Scots nobleman Lord Kinross. She proved to be a brilliant student of the biological sciences and selected genetics as her specialty.
Previous CBM incarnation
Olivia Williams in X-Men: The Last Stand
Caleb Landry Jones as Banshee
Comic Bio: Banshee is an Irish mutant that possesses a "sonic scream," which is capable of harming enemies’ auditory systems and causing physical vibrations.
Previous CBTV incarnation
Jeremy Ratchford in a 1996 TV movie titled Generation X
Jennifer Lawrence as Mystique
Comic bio: Throughout most of her history, Mystique has been a supervillain, founding her own Brotherhood of Mutants and assassinating several important people involved in mutant affairs. Mystique herself is a mutant, a shapeshifter whose natural appearance includes blue skin and yellow eyes.
Previous CBM incarnation
Rebeca Romijn in X-Men, X2: X-Men United, X-Men: The Last Stand
Nicholas Hoult as Beast
Comic bio: When first introduced, the Beast possesses ape-like superhuman physical strength and agility and oversized hands and feet, though he otherwise appears to be a normal human being. Throughout his history, the Beast undergoes progressive transformations to his physiognomy, permanently gaining increasingly animalistic physical characteristics.
Previous CBM incarnation
Steve Bacic cameo’s as Dr. Hank McCoy in X2: X-Men United
Kelsey Grammer as Beast in X-Men: The Last Stand
Lucas Till as Havok
Comic bio: Havok generates powerful “plasma blasts”, an ability he has had difficulty controlling. He is the son of Corsair, the younger brother of the X-Men’s Cyclops and older brother of Vulcan. He often resents Cyclops’ authoritative attitude and reputation as a model X-Man.
X-Men First Class will be Havok’s first adaptation to live media.