- David Strathairn as Dr. Lee Rosen – A doctor specializing in the study of people with super abilities whom he has dubbed "Alphas", he leads a government-sponsored team of such Alphas to help identify and aid other Alphas or stop/contain dangerous ones. Dr. Rosen has no abilities like the Alphas but is good at understanding and dealing with people. He swims two miles per day in his pool and grows his own herbs.
- Ryan Cartwright as Gary Bell – A young man with autism who is socially functional to a degree. A prodigious savant, his diagnosis is transduction meaning he has the ability to see all electromagnetic radiation/electromagnetic wavelengths and process information as fast as any computer. In season two, he is able to find the wavelengths of forks, trees, and other non-electric items when faced with no technology.
- Warren Christie as Cameron Hicks – A former Marine with the superhuman ability of "hyperkinesis", which allows his brain to process movement at a much faster rate than others. This gives him amazing athletic feats of timing, superhuman reflexes and perfect accuracy with firearms or thrown objects and also allows him, for example, to predict trajectory by eyesight. However, he cannot always do it when under stress, making his abilities unreliable. In the first episode he is found to have an abnormal growth in his brain. He is found by the team working in a supermarket after they find video of him as a child pitching a perfect baseball game. He has one child who is rarely in his life. In season one, he has a relationship with Nina. In season two, he has a relationship with Dr. Rosen's daughter, Dani. He becomes obsessed with the thought of his son having an alpha ability, and is constantly putting him in situations to test him for an alpha ability.
- Azita Ghanizada as Rachel Pirzad – A former CIA linguist with the ability to "heighten" one of her five senses (sight, smell, taste, hearing, and touch) to extreme levels, by disabling all of the others. Her diagnosis is "synesthesia" meaning able to enhance senses (it should be noted that synesthesia is actually a neurological condition in which stimulation of one sense automatically sets off others, not the enhancement of a single sense). She uses this, for instance, to view things at a microscopic level or detect complex chemical composition by scent. The fact that all of her senses are permanently heightened to a degree above normal, along with her synesthesia, make it difficult for her to interact socially. She has difficulty maintaining relationships with the opposite sex due to this. In season two, she learns how to further control her senses.
- Laura Mennell as Nina Theroux – A young woman who is able to mentally "push" people into doing whatever she verbally asks of them. Her diagnosis is Hyper Induction meaning she can override willpower in others. She used to use this for personal gain, culminating in her believing she accidentally pushed her boyfriend and father into committing suicide. She is now helping Dr. Rosen in an effort to redeem herself. It is noted that her character seems to have been with Rosen the longest, and she is the closest to him. A running gag in the first season was that Nina always had a different car that she has "borrowed", implying that she pushed someone for it. If Nina pushes too hard or too much on a person, she can cause them to become brain dead. Nina has very good control of her ability; people with this ability have a hard time controlling how they use it and become power hungry. When she talks to FBI agents, they will not make direct eye contact, or insist on wearing dark sunglasses, in fear of being pushed. Her past is dark and plagued by her pushing others, including her father. Her father commits suicide after being pushed one too many times being told he does not want to leave her mother when Nina was a child. In season two, Nina loses control over her ability for an episode, due to the hunger of it, but tries to make up for her past mistakes after. She is shown to be reluctant to use her ability on people.
- Malik Yoba as Bill Harken – A former FBI agent with the ability to activate his endocrinal "fight or flight" response at will, resulting in increased durability, endurance, speed and strength. His diagnosis is enhanced strength from flight-or-fight response. He cannot keep this up for very long, however, due to the stress it causes his body. He was suspended from the FBI due to anger issues resulting from the stress of using his ability. He is rude and pushy when it comes to working with his teammates initially, specifically Rachel and Gary, but as season one continues he is no longer known as "mean Bill".
- Erin Way as Kat (Season 2) – A mysterious, free-spirited young loner whose Alpha ability allows her procedural memories to pick up any skill at a glance; at the cost of her long-term declarative memories. She forgets all of the information she has learned after one month due to the information she has processed during that time period, though she retains the skills she acquired during that time. Dr. Rosen gives her a video camera to help her remember. In season two, she struggles with one of her past memories of a lady in a blue dress.
Pages in category "Cast and Characters"
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