 A genius scientist who , because of exposure to gamma radiation , transforms into a monster when enraged or agitated . Ruffalo , who was considered to play Banner in The Incredible Hulk before Edward Norton took the role , was cast after negotiations between Marvel and Norton broke down . About replacing Norton , Ruffalo said , " I 'm a friend of Ed 's , and yeah , that wasn 't a great way for all that to go down . But the way I see it is that Ed has bequeathed this part to me . I look at it as my generation 's Hamlet . " About the character , he said , " He 's a guy struggling with two sides of himself — the dark and the light — and everything he does in his life is filtered through issues of control . I grew up on the Bill Bixby TV series , which I thought was a really nuanced and real human way to look at the Hulk . I like that the part has those qualities " . Regarding the Hulk 's place on the team , Ruffalo said , " He 's like the teammate none of them are sure they want on their team . He 's a loose cannon . It 's like , ' Just throw a grenade in the middle of the group and let 's hope it turns out well ! " This is the first production in which the actor playing Banner also plays the Hulk . Ruffalo told New York magazine , " I 'm really excited . No one 's ever played the Hulk exactly ; they 've always done CGI . They 're going to do the Avatar stop @-@ action , stop @-@ motion capture . So I 'll actually play the Hulk . That 'll be fun " . The 3D model used to create the Hulk 's body was modeled after Long Island bodybuilder and male stripper Steve Romm , while the Hulk 's face was modeled after Ruffalo . To create the Hulk 's voice , Ruffalo 's voice was blended with those of Lou Ferrigno and others ; however , the Hulk 's only speaking line ( " <unk> god . " ) was provided solely by Ruffalo . 
