Main •
Famke Janssen as Olivia Godfrey •
Bill Skarsgård as Roman Godfrey •
Landon Liboiron as Peter Rumancek •
Penelope Mitchell as Letha Godfrey (season 1) •
Freya Tingley as Christina Wendall (season 1) •
Kaniehtiio Horn as Destiny Rumancek (season 2–3; recurring season 1) •
Joel de la Fuente as Dr. Johann Pryce (season 2–3; recurring season 1) •
Dougray Scott as Dr. Norman Godfrey (season 1–2) • Nicole Boivin (recurring season 1) and
Madeleine Martin (season 3; recurring season 2) as Shelley Godfrey, Roman's heavily deformed but good-hearted sister. While Boivin and Martin are the main actresses portraying the character, Shelley's remarkably large figure is provided, when seen from a distance, by
Amazon Eve for the first five episodes, and by Michael Andreae thereafter. •
Camille De Pazzis as Annie Archambeau (season 3)
Recurring •
Lili Taylor as Lynda Rumancek, Peter's mother and confidant (season 1–2) •
Laurie Fortier as Marie Godfrey, Norman's wife, and the mother of Letha (season 1–2) •
Kandyse McClure as Dr. Clementine Chasseur, a mysterious woman arriving in Hemlock Grove to investigate the killings (season 1) •
Aaron Douglas as Tom Sworn, the sheriff of Hemlock Grove (season 1) •
Ted Dykstra as Francis Pullman, the "
village idiot", who claims to have witnessed unspeakable things (season 1) •
Demore Barnes as Michael Chasseur, Clementine's brother •
Luke Camilleri as Andreas Vasilescu (season 2–3) •
JC MacKenzie as Dr. Arnold Spivak (season 2–3) •
Madeline Brewer as Miranda Cates (season 2–3) •
Shauna MacDonald as Dr. Galina Zheleznova-Burdukovskaya (formerly Alyona Potyomkina-Zosimova), a brilliant Russian scientist working under Dr. Pryce (season 2) •
Alex Hernandez as Isaac Ochoa, a private detective (season 3) •
Richard Gunn as Aitor Quantic (season 3) •
Emmanuel Kabongo as Marshall (season 3) •
Michael Therriault as Dr. Klaus Blinsky (season 3) •
Anthony J. Mifsud as Greek Delivery man (season 3) • Meegwun Fairbrother as Milan Faber (season 3)
Guest •
Eliana Jones and
Emilia McCarthy as Alexa and Alyssa Sworn, Sheriff Sworn's twin daughters, and Christina's best friends •
Holly Deveaux as Jenny Fredericks, a local convenience store clerk •
Don Francks as Nicolae Rumancek, Peter's deceased grandfather. Seen in flashbacks. •
Philip Craig as the Bishop, a contact of Clementine's •
Alanis Peart as Mrs. Pisarro, Peter's and Roman's English teacher •
Emily Piggford as Ashley Valentine, a schoolmate of Roman's who develops a crush on him •
Jacqueline Graham as Lisa Willoughby, a local girl who becomes the second murder victim •
Paul Popowich as JR Godfrey, Roman's deceased father, husband of Olivia, and brother of Norman. Seen in flashbacks •
Landon Norris as Tyler, a fellow schoolmate, with a romantic interest in Christina •
Joe Bostick as Vice Principal Spears, the vice principal of the local high school •
Lorenza Izzo as Brooke Bluebell, a local girl, whose brutal murder opens the series •
Marty Adams,
William deVry,
Jasmin Geljo,
Ashleigh Harrington and
Dylan Trowbridge portray the town's Deputy Sheriffs, nicknamed respectively Neck, Chin, Moustache, Lips, and Nose ==Development and production==