Scott McCall lives in Beacon Hills, California with his mother Melissa McCall. He is best friends with Stiles Stilinski. Scott goes to Beacon Hills High School and has a part-time job as a veterinarian assistant in Beacon Hills. Scott becomes a new werewolf, after being bitten by an alpha, Peter Hale. In Season 1 and Season 2, Scott struggles to control his transformations, adapt to his new life and balance his high school relationships with the help of Stiles and fellow werewolf Derek Hale. He falls in love with Allison Argent, a member of a werewolf hunter family which becomes a source of drama and turmoil in his life and works to protect his friends and family from a slew of human and supernatural enemies. Scott is naturally good-natured and kind-hearted. He is affable, loyal and optimistic. He has a tendency to be socially awkward and quirky, being considered a high school dork. Despite his asthma and being a benchwarmer for the school's lacrosse team, Scott persistently wishes to climb out of his high-school anonymity and find his place.

Lydia Martin is Beacon Hills High School's most popular student and the girlfriend of Jackson Whittemore. In Season 1, Lydia becomes Allison Argent's best friend. She is then bitten by alpha werewolf Peter Hale. In Season 2, Lydia recovers from her attack, but then exhibits supernatural attributes as her latent supernatural powers awaken.  In Season 3, Lydia has formed a close bond with Stiles Stilinski and starts an affair with the werewolf Aiden Lydia discovers she is a banshee, and becomes a founding member of Scott's pack. Lydia resolves to learn how her banshee abilities work and how to control them.Lydia is depicted as being the archetypal high school queen bee. She is carefree, shallow-minded and spoiled, being the attractive teenage girl who is wealthy and gets everything she wants. She is sexually active, enjoys the admiration she receives from the male populace and rules the high school social structure.

 Stiles Stilinski is the son of the sheriff of Beacon Hills. He is best friends with Scott McCall. In Season 1, Stiles finds out Scott has been changed into a werewolf, becoming the first to acknowledge the supernatural. Throughout Seasons 1 and 2, Stiles does his best to support Scott in coming to grips with his new identity, navigate the supernatural world and keep the people they care for safe and fight back against a slew of enemies. He harbors an intense, unrequited crush on Lydia Martin. In Season 3, Stiles' relationship with Lydia resolves into becoming a close friendship. Stiles is constantly described as overly anxious and curious, particularly towards criminology and mysteries. He is extremely hyperactive, outspoken and immensely intelligent, has a quick mind for puzzles and research, but is prone to distraction and flailing due in part to his ADHD. Stiles also has an extreme penchant for sarcastic quips. Despite his scatterbrained shenanigans, he is well-meaning and very protective of those he cares for, particularly his best friend Scott and his father, the sheriff.

In Season 4, Liam Dunbar is a new freshman at Beacon Hills High school, best friends with Mason Hewitt and a new player on the Cyclones lacrosse team. Liam is attacked by a wendigo, Sean Walcott, then is bitten by Scott McCall to save his life. He then joins Scott's Pack, becoming Scott's first beta and learning everything supernatural from the Pack. Liam is confident, outgoing and tends to to let his being naturally talented at lacrosse get to his head.

In Season 1, Derek is a beta werewolf, in conflict with the Argent family of hunters, a reluctant ally of Scott McCall and Stiles Stilinski, and is searching for an alpha werewolf who murdered his sister, Laura Hale. To avenge Laura's death and prevent Scott from dealing with the burden of being an alpha when he didn't even want to be a werewolf, he kills the alpha, his uncle Peter Hale. Now an alpha, he bites Jackson Whittemore. In Season 2 Derek forms a pack biting Isaac Lahey, Erica Reyes, and Vernon Boyd. He discovers that Jackson's bite went wrong, turning him into a kanima which started killing people at the command of a kanima master. Derek takes responsibility for this and attempts to stop it from killing more people. In 3A, Derek finds himself at war with the Alpha Pack, discovers his long-lost younger sister Cora Hale is alive and reunites with her, but is shattered following the deaths of Erica and Boyd. He is magically roofied by Jennifer Blake who uses the power of the virgin sacrifices to emulate certain aspects of Stiles and reenact some of the scenes where Stiles and Derek had built up a strong bond of trust. In his teens, Derek was typically carefree, fun-loving, and extroverted among his high school peers. He was a hopeless romantic, falling in love with fellow student Paige Krasikeva. He was devastated, broken, and wracked with guilt when he was forced to mercy kill her to spare her an even more painful death from rejecting the bite given to her by Ennis. While still in a vulnerable state from this tragedy, he was seduced by Kate Argent in her quest to murder his family. He believes this to be his fault even though in both cases he was a victim of others' manipulations.

Kira Yukimura is Ken and Noshiko Yukimura's daughter. In Season 3, Kira is a new student at Beacon Hills High School. Kira starts and pursues a romantic connection with Scott McCall. She learns that she is a Thunder kitsune. She then discovers her parents' secrets, that her mother is also a kitsune, and who summoned the Oni to Beacon Hills. Kira discovers her power and assists Scott's pack in their battle against the Nogitsune. In Season 4, Kira is now an official member of the pack, best friends with Lydia Martin and Malia Tate, starts a romantic relationship with Scott.Due to being the new girl at a new school, as well as dealing with her father being the history teacher, Kira comes across as being shy, listless, awkward and nervous, but perky and modest, looking to fit in and make friends at school. She is also sensitive and withdrawn, being confused by her supernatural status. Once introduced to Scott and his Pack, learning of their supernatural species and roles, she starts to come out of her shell, content and inspired.  

Peter Hale is a born werewolf from the Hale Family who lived in Beacon Hills, California, the younger brother of the late Talia Hale and Derek Hale's uncle. During the Hale House Fire, six years before the series, Peter had survived but was rendered comatose at Beacon Memorial. In Season 1, Peter is revealed to be the alpha werewolf who had killed Laura Hale, his niece, to gain alpha rank, lured Derek back to Beacon Hills and had bittenScott McCall. He kills all the criminals involved in his family's massacre, bites Lydia Martin and finally, kills Kate Argent, the perpetrator of the arson. He is defeated by Stiles Stilinski, Allison Argent, and Jackson Whittemore using Lydia's Molotov cocktails and is then killed by Derek. In Season 2, Peter haunts Lydia as his bite awakened her latent banshee powers. He possesses her in order to orchestrate his resurrection, coming back to life as an omega. Peter provides the necessary information to turn Jackson from a kanima into a werewolf in exchange for being in Derek's Pack. Peter is outwardly charming, polite, sarcastic and witty. He is highly intelligent and a master manipulator with a knack for reading people and getting under their skin to have them see things his way and be in agreement with him.  

Noah Stilinski is the sheriff of Beacon Hills, California, the father of Stiles Stilinski, the widower of his mother, Claudia Stilinski and close friends with Melissa McCall, Scott McCall's mother. In Seasons 1 and 2, the Sheriff works on solving the murders as well as other criminal activity in Beacon Hills, but is unaware of the supernatural nature and presence in the town. In Season 3, he comes across the killing spree committed by the Darch, and is brought into the supernatural side when he's abducted by the dark Druid along with Melissa McCall and Chris Argent, but they are saved by Scott's Pack. In Season 3B, Stilinski gains a new assistant deputy Jordan Parrish, and works with the Pack and their allies to save Stiles when he is possessed by a Nogitsune. Noah is a intelligent and dedicated officer of the law, always doing his best to ensure the safety of the citizens of Beacon Hills, California. He has a strong moral compass, a sense of justice and protective instincts. Like Stiles, he can have a sarcastic tongue though not as pronounced. Also like Stiles he possesses great aptitude and inquisitiveness for solving mysteries, despite his inability to see the complete picture of what happening in Beacon Hills. Stilinski can be stern and authoritive, but compassionate at the same time, and though they can be as combative as in any parent-teenager relationship, and despite his frequent annoyance and frustration at Stiles' tendency to meddle in his investigations, he is an extremely protective, forgiving and loving parent to his son, partially due to his wife's death. Claudia's death still haunts and affects him deeply, he greatly misses her, though he and Stiles don't talk about her much.