Kevin Bacon as Ryan Hardy, a former Federal Bureau of Investigation agent who, in 2003, led the Federal Bureau of Investigation team that captured serial killer Joe Carroll. Put on disability and removed from active duty after being knifed in the heart by Carroll, calling for him to use a pacemaker, Hardy is called up to act as an advisor after Carroll escapes from prison. At the start of the series he’s presented as being withdrawn from the world round him, bordering on alcoholism, tortured by his personal guilty conscience as he failed to place Carroll as a suspect after their 1st meeting, and Carroll took 5 added victims before he was captured; nevertheless, later in the series Hardy starts to open up to his co-workers and, later on, Claire Matthews. Hardy has also penned a true crime book on the Joe Carroll case titled The Poetry of a Killer.
James Purefoy as Dr. Joe Carroll, a onetime professor of English literature at Winslow University. Carroll’s teaching emphasises the romantic period. A frustrated novelist, he thinks, like his hero Edgar Allan Poe, in the “insanity of art”, he at first started to make “art” by eviscerating his female students. He in the end killed 14 of them before he was captured by Ryan Hardy. Whilst serving out his sentence at the Virginia Central Penitentiary in Waverly, Virginia, Carroll gets together a cult-like collection of followers, who are prepared to murder, kidnap, and even sacrifice themselves in order to carry out his plan of revenge against Hardy and his ex-wife. In the season conclusion Carroll is seemingly killed in a large explosion outside a lighthouse after a savage encounter with Hardy. Carroll penned a book called The Gothic Sea, prompted by Poe’s last incomplete work, The Light-House, and was utilising his plots with his followers in a brand-new book, where Ryan is the protagonist and Claire the love interest.
Natalie Zea as Dr. Claire Matthews, Joe Carroll’s ex-wife, who also had a relationship with Ryan Hardy after Carroll’s arrest. Like her ex-husband, she’s a college professor.
Annie Parisse as Debra Parker, an Federal Bureau of Investigation specialist on cult behavior, and head of the Bureau’s Alternative Religion Unit. Her expertise leads to her being called in to lead the investigation of Carroll and his cult. Parker grew up in a cult, fleeing, without the blessing of her parents, when she was sexually abused by the cult’s leader. Parker dies in the season conclusion.
Shawn Ashmore as Mike Weston, a young Federal Bureau of Investigation agent. Weston wrote his thesis on Joe Carroll whilst in training and sees Ryan Hardy as a personal hero. He’s regarded as the team’s expert on Joe Carroll, and exhibits a proficiency with computers that he utilises to help in tracking Carroll and his followers.
Valorie Curry as Emma Hill (also known by the alias “Denise Harris”), a follower of Joe Carroll. Emma met Carroll at a book reading in 2003, and finishes becoming one of his 1st and most dedicated followers. At his instruction, she takes the name Denise Harris and acquires the position of nanny in Carroll’s ex-wife’s household, caring for Carroll’s son Joey. Emma takes on leadership of a little cell of followers tasked with kidnapping Joey, and shows zero reluctance to utilise violence.
Nico Tortorella as Jacob Wells (also known by the alias “Will Wilson”). Jacob is Emma’s lover and another of Carroll’s followers. As Will Wilson he and Billy Thomas lived next door to Sarah Fuller, the sole woman who escaped Carroll. Will and Billy pose as a homosexual couple as part of their cult activities, utilising the ruse as they think Sarah won’t feel jeopardised by two homosexual men. Jacob is then killed by Emma.
Adan Canto as Paul Torres (also known as “Billy Thomas”). Torres, as Billy Thomas, lived next door to Sarah Fuller with Jacob. Their homosexual relationship was at first portrayed as being a cover, but Paul developed actual feelings for Jacob. As Paul Torres he’s to share Jacob with Emma, and is unhappy with the relationship, frequently referred to as a “third wheel.” Paul is critically injured by Hardy, but escapes with Jacob. He finally asks Jacob to suffocate him.
Kyle Catlett as Joey Matthews, Joe Carroll and Claire Matthews’ son.