O'Bannon has created five original television series (Farscape, seaQuest DSV, Defiance, Cult, and Alien Nation).

O'Bannon made his writing debut selling spec material to NBC's Amazing Stories (1985) and CBS's The Twilight Zone (1985), but first garnered critical attention for his film Alien Nation (1988) and its subsequent spinoff television show.

O'Bannon's most critically acclaimed success was the space epic Farscape on the Sci-Fi Channel (1999–2003) which ran for four seasons and spun off into a mini-series as well as a comic book series.

Since Farscape, he has created the television show Defiance (2013) and The CW's Cult (2013), the miniseries The Triangle (2005), as well as an uncredited rewrite on the pilot for Warehouse 13 (2009).

O'Bannon has been credited with creating original series "that push the boundaries of speculative television in ways that put him in the rare company of writers like Rod Serling.

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.

Originally sold to the Sci-Fi Channel, the head of the network told O'Bannon "Just make it as weird as you can, because I just don't want a kids' show.

After a four-season run, the show was caught in a business conflict when The Henson Company was sold to foreign investors, and ended without an already-ordered fifth season.

[7] O'Bannon almost immediately then sold The Triangle to the Sci-Fi Channel which he wrote and executive produced with Bryan Singer and Dean Devlin.

With Defiance up and running, O'Bannon moved on to Warner Bros. Television when it was announced the CW had placed a pilot order to make Cult in January 2012 nearly seven years after the network's predecessor had bought it.