Clive Owen (Arthur), Ioan Gruffudd (Lancelot), Keira Knightley (Guinevere), Mads Mikkelsen (Tristan), Til Schweiger (Cynric), Ray Stevenson (Dagonet), Ray Winstone (Bors), Hugh Dancy (Galahad), Stephen Dillane (Merlin), Stellan Skarsgård (Cerdic), Sean Gilder (Jols), Stefania Orsola Garello (Fulcinia), Graham McTavish (Römischer Offizier), Ivano Marescotti (Bischof Germanius), Clive Russell (Lancelots Vater), Joel Edgerton (Gawain), Ken Stott (Marius Honorius), Lorenzo de Angelis (Alecto), Shane Murray Corcoran (junger Arthur), Maria Gladkowska (Arthurs Mutter), Bosco Hogan (Bischof Decoy), Ned Dennehy (verrückter Mönch), Pat Kinevane (Horton), Charlie Creed Miles (Ganis), Alan Devine (britischer Späher), David Murray (Merlins Unterführer)