Eli Marienthal Hogarth Hughes (voice) Jennifer Aniston Annie Hughes (voice) Harry Connick Jr. Dean McCoppin (voice) Vin Diesel The Iron Giant (voice) James Gammon Foreman Marv Loach / Floyd Turbeaux (voice) Cloris Leachman Mrs. Lynley Tensedge (voice) Christopher McDonald Kent Mansley (voice) John Mahoney General Rogard (voice) M. Emmet Walsh Earl Stutz (voice) Jack Angel Additional Voices (voice) Bob Bergen Additional Voices (voice) Mary Kay Bergman Additional Voices (voice) Michael Bird Additional Voices (voice) Rodger Bumpass Additional Voices (voice) Robert Clotworthy Additional Voices (voice) Jennifer Darling Additional Voices (voice) Paul Eiding Additional Voices (voice) Bill Farmer Additional Voices (voice) Charles Howerton Additional Voices (voice) Ollie Johnston Additional Voices (voice) Sherry Lynn Additional Voices (voice) Mickie McGowan Additional Voices (voice) Phil Proctor Additional Voices (voice) Frank Thomas Additional Voices (voice) Patti Tippo Additional Voices (voice) Brian Tochi Additional Voices (voice) Jack Paar Self (archive sound) (uncredited)