John McNamara Creator, Executive Producer David Duchovny Sam Hodiak Actor, Executive Producer Emma Dumont Emma Karn Actor Grey Damon Brian Shafe Actor Tara Lynne Barr Katie Actor Michaela McManus Grace Karn Actor James Martinez Ruben Salazar Actor Gaius Charles Bunchy Carter Actor David Meunier Roy Kovic Actor Claire Holt Charmain Tully Actor Gethin Anthony Charles Manson Actor Chance Kelly Detective Ed Cutler Actor Ambyr Childers Sadie Actor Brian F. O'Byrne Ken Karn Actor Cameron Deane Stewart Tex Watson Actor Madisen Beaty Patty Krenwinkel Actor Mark L. Young Guest Star Abby Miller Guest Star Jefferson White Guest Star Chris Sheffield Walt Hodiak Guest Star Marty Adelstein Executive Producer Melanie Greene Executive Producer Jonas Pate Director Michael Zinberg Director Alexandra Cunningham Writer Sera Gamble Writer David Reed Writer Lukas Ettlin Cinematographer Michael Stecher Cinematographer