Main •
Lauren Ambrose as Dorothy Turner (née Pearce), a local television news reporter and highly overprotective mother who lives under the delusion that her infant son is still alive and well. •
Toby Kebbell as Sean Turner, Dorothy's husband and a stay-at-home consulting chef. •
Nell Tiger Free as Leanne Grayson, a mysterious young nanny from Wisconsin hired by the Turners to look after "Baby Jericho". The series frequently hints that she might possess powers,
supernatural abilities that develop gradually and grow stronger every night she stays at the Turners' house. •
Rupert Grint as Julian Pearce, Dorothy's alcoholic younger brother. Despite his discourteous behavior, he frequently helps the Turners.
Supporting • Mason and Julius Belford (season 1) and Jack and James Hoogerwerff (seasons 2–4) as Baby Jericho Turner, the firstborn child of the Turners who died just two and a half months after he was born. He is later replaced by a lifelike reborn doll to soothe Dorothy under the delusion that her son is still alive, but inexplicably re-appears alive and well following Leanne's arrival. • Phillip James Brannon as Matthew Roscoe, a man hired by Julian to help investigate Leanne and protect the Turners. His life is changed after an encounter with the Church of Lesser Saints. •
Tony Revolori as Tobe, Sean's kind-hearted
commis chef who has a crush on Leanne. • Soojeong Son as Wanda (Season 1), a babysitter whom Leanne befriends. •
Boris McGiver as "Uncle" George, a member of the Church of Lesser Saints bent on bringing Leanne back to the cult, and posing as her uncle to the Turners. •
Jerrika Hinton as Natalie Gorman (season 1–2), Dorothy's close friend and therapist who suggested the
reborn doll as a temporary coping method, and one of the only people outside of the family to know about Jericho's death. •
Molly Griggs as Isabelle Carrick (season 1–3), an up-and-coming reporter at 8News where Dorothy works. •
Todd Waring as Frank Pearce, Dorothy and Julian's father and Jericho's maternal grandfather. •
Alison Elliott as "Aunt" May Markhem (season 1–2, 4), George's wife and the leader of the Church of Lesser Saints, who poses as Leanne's aunt to the Turners. •
Victoria Cartagena as Officer Stephanie Reyes (season 2, 4), a police officer who interacted with the Turners when Jericho died. • Billy Vargus as Walker Roush (season 2–4), a news anchor for 8 News. • Katie Lee Hill as Kourtney (season 2–4), Frank's much-younger girlfriend. •
Barbara Sukowa as "Aunt" Josephine (season 2), a member of the Church of Lesser Saints. •
Sunita Mani as Veera (season 3), Julian's girlfriend and a recovering drug addict. • Mathilde Dehaye as Snake (season 3–4), a homeless person in the park who left the Church of Lesser Saints to worship Leanne. • Joshua De Jesus as Milo (season 3), a homeless person part of Snake's group. • Mac Rop as Lou (season 3–4), a homeless person part of Snake's group. • Carmen Herlihy as Nancy (season 3), a
minister Sean has been seeing. • Brian K. Landis as the Tall Man (season 4), a member of the Church of Lesser Saints • Barbara Kingsley as Roberta "Bobbie" (season 4), a live-in nurse for Dorothy's sick-nurse who is also a
spiritual medium. •
Denny Dillon as Beverly "Bev" (season 4), Dorothy's other live-in nurse.
Guest •
M. Night Shyamalan as a Delivery Guy ("Reborn"). •
Nadia Alexander as Sylvia, Tobe's verbally-abusive girlfriend hoping to get a job from Sean ("Ring"). • Carmen M. Herlihy as Nancy, Sean's minister from Liberty Unitarian ("Tiger" & "Fish"). •
Frank Wood as Dr. Dale Mackenzie, a psychologist who is a friend of Frank ("Commitment"). ==Episodes==