O'Bannon's career got its start with a couple of spec scripts he had written for submission to ABC's "Darkroom". However, the show was canceled before his material could be produced. He followed it up by submitting those scripts to both the CBS revival of "The Twilight Zone" and NBC's new anthology series "Amazing Stories", receiving positive reaction from both shows. Based on his pitches for some additional stories, "The Twilight Zone" producers hired him as Story Editor. During his time on "The Twilight Zone", he wrote and rewrote several episodes, including more original episodes than anyone else. Among his original episodes was "Wordplay", starring Robert Klein, his first, and "The Storyteller" which was nominated for that year's Writer's Guild Award.