He has been credited under the names Jim Isaac as well as Jim "Smash" Isaac. His first work in the horror genre was as a creature effects designer on Joe Dante's 1984 horror/comedy Gremlins. James also worked on visual effects for the 1989 sci-fi film DeepStar Six. That same year, he worked on the team that transformed Jeff Goldblum's geeky scientist Seth Brundle into the human/insect hybrid dubbed "Brundlefly" in David Cronenberg's The Fly. Also in 1989, Isaac made his directorial debut with The Horror Show, aka, House III.