Vo filme Potomkovia ľudí hrajú Clive Owen (Theo Faron), Clare-Hope Ashitey (Kee), Chiwetel Ejiofor (Luke), Julianne Moore (Julian), Michael Caine (Jasper), Pam Ferris (Miriam), Charlie Hunnam (Patric), Danny Huston (Nigel), Peter Mullan (Syd), Oana Pellea (Marichka), Jacek Koman (Tomasz), Phaldut Sharma (Ian), Juan Gabriel Yacuzzi (Baby Diego), Mishal Husain (Newsreader), Rob Curling (Newsreader), Maria McErlane (Shirley), Michael Haughey (Mr. Griffiths), Miriam Karlin (Caged German Grandmother), Philippa Urquhart (Janice), Tehmina Sunny (Zara), Jody Halse (Immigration Policeman), Ilario Bisi-Pedro (Cigar Man), Michael Klesic (Rado), Martina Messing (Birgit), Simon Poland (Preacher Trafalgar Square), Barnaby Edwards (Ministry Official), Ed Westwick (Alex), Valerie Griffiths (Dog Track Woman), Billy Cook (Bookmaker), Gary Hoptrough (Simon), Rob Inch (Road Traffic Police), Jamie Kenna (Road Traffic Police), Maurice Lee (Samir), Dhafer L'Abidine (Dhafer), Bruno Ouvrard (Bruno), Denise Mack (Emily), Joy Richardson (Joy), Caroline Lena Olsson (Caroline), Milenka James (Milenka), Somi De Souza (Somi), Francisco Labbe (Francisco), Thorston Manderlay (Thorston), Georgia Goodman (Georgette), Jon Chevalier (Café Customer), Rita Davies (Café Customer), Kim Fenton (Café Customer), Chris Gilbert (Café Customer), Phoebe Hawthorne (Café Customer), Rebecca Howard (Cafe Customer), Atalanta White (Café Customer), Laurence Woodbridge (Café Customer), Dorothy Grumbar (German Bus Passenger), Barry Martin (German Bus Passenger), Ernesto Tomasini (Italian Bus Passenger), Keith Dunphy (Bexhill Immigration Officer), Raymond Trickitt (Bexhill Immigration Officer), Nabil Shaban (Bexhill Market Hustler), Goran Kostić (Bexhill Market Hustler), Dermot O'Neill (One-Legged Hustler), Faruk Pruti (Sirdjan), Alexandre Bestavashvili (Georgian Man), Galina McWhirr (Georgian Woman), Nirmala Martis (Wailing Woman), Ida Church (Bleeding Woman), Yolanda Vazquez (Spanish Woman), Andrew Brooke (Soldier), Nihal Arthanayake (Radio Announcer (voice)), Andy Callaghan (Riot Policeman / Soldier (uncredited)), Forbes KB (Elite Soldier (uncredited)), P. D. James (Café Customer (uncredited)), Jamie Lengyel (First Human Project Professor (uncredited)), João Costa Menezes (Terrorist (uncredited)), Vidal Sancho (Basque Rebel (uncredited)), John Warman (Taxi Driver (uncredited)), Paul Warren (Injured Refugee (uncredited)), Yana Yanezic (Woman (uncredited)), Michael Snelders (Newsreader (uncredited)), Steve Murphy (Soldier (uncredited)).