Kevin "Thad" Castle (Ritchson): A Senior linebacker/team captain from Connecticut. Despite his status as a two time consensus All-American and team record holder for most tackles in a game (a game which he was subsequently ejected from for calling referees "butt faces[2] "), Thad often annoys his teammates due to his bullying and high strung antics when things do not go his way. However, he harbors a great love for his team and understands what it takes to be a leader in desperate situations, which garners respect from his comrades despite his behavior. His father died in the military while deployed to Bosnia, where he had an affair resulting in Thad's attractive half-sister, Alma, of whom he is overly protective. He is also heavily prone to engage in excessive homoerotic behavior, especially in the hazing rituals of freshman players. His dedication to the team and willingness to sacrifice anything to ensure the team wins prompted coach Marty Daniels to name him Captain at the beginning of his sophomore year. This is the only time Daniels ever named someone so young captain. Thad lives at the Goat House with Alex and Sammy. His nickname "Thad" came from a childhood lisp that he came to embrace after some kids at school made fun of him for the way he said "sad."

Larry Summers (Newton): Larry lives in the Goat House, is Thad's best friend, and is often seen following him around. He has shown to do anything to help his team, even diving his finger up Thad's butt on Coach Daniels orders.

Donald "Donnie" Schrab (Ramsay): Donnie Schrab is the center for the Blue Mountain State football team. He is somewhat childish and very easygoing. Donnie lives in the Goat House. It was revealed in Blue Mountain State: The Rise of Thadland that Donnie is gay.

Sammy Cacciatore (Romano): The team mascot (Billy, The Mountain Goat Mascot) from Cheyenne, Wyoming and Alex's roommate, childhood friend and Mary Jo's half brother. He's constantly searching for girls and excuses to get drunk, with his drinking often leading him into misadventure. He lives in a closet at the Goat House with Thad and Alex. Sammy is often used by Thad to conduct favors and chores to keep his old closet at the Goat House. Sammy suffers from severe personal, deep-seated mental health issues and borderline mental retardation which lead to him getting him into difficult situations. In season 1 without Alex around Sammy and Craig get into a confrontation with another student to which Sammy worms his way out by stating that he would "jerk another person off". In Blue Mountain State: The Rise of Thadland, he ends up eating Billy the Goat, live mascot, after Billy had raped Sammy previously when strapped to a bed naked and left alone.

Debra Simon (Richards) (Recurring Season 2; Starring Season 3): Debra is Marty's ex-wife and current girlfriend. After divorcing Marty, she married Dean Simon's, and enjoyed using him to get payback on Marty. She slept with Alex, and later divorced Simon and reunited with Marty. In Season 3, it is implied she slept with Mary Jo as a thank-you for "vagazzling" her vagina. She and Marty have a son named Joey.

Mary Jo Cacciatore (Shaw) (Starring Season 2, Recurring Season 3) : Mary Jo is Sammy's younger sister. She is slightly ditzy and interested in Alex, whom she has known since childhood. She is a cheerleader, though the other girls do not like her due to her laziness and coming to practice drunk. In the second season she had sex with Alex Moran in the drunk tank's elevator. In the third season, she becomes a lesbian and it is implied that she had slept with Debra as payment for "vagazzling" her vagina.

Craig Shilo (Jones) (Starring Season 1) : A running back from Columbus, Ohio. National High School Player of the Year, Craig Shilo was the team's star freshman player. Unlike his teammates, Craig is rather straight-laced and committed to his ultra-manipulative girlfriend Denise, with whom he breaks up when he finds out she cheated on him with other men, including a man from her marketing class whom she tells Craig is an NFL scout. It is revealed by the coaches in the Season 2 premiere that Shilo has apparently transferred to University of Georgia, but Alex corrects them and states he has transferred to Georgia Tech (his character being written out due to Jones' major drug-related arrest).

Alex Moran (Brooks): A Junior starting quarterback, acting Captain, from Cheyenne, Wyoming. He was the first 10,000 yard passer in Wyoming High School history. Unlike the rest of the characters, Alex does not see college football as a stepping stone for the NFL and is content to spend his days as a back-up player and a life as an "Average Joe" once he graduates from college. Instead, he is dedicated to having as much fun as humanly possible while in college, which includes getting drunk and having sex. He embraces being the back-up quarterback in season 1 and doesn't want to start. In the second season finale he begins dating Mary Jo, but this ends once she turns out to be a lesbian. He lives at the Goat House with Thad and Sammy, who use it also as a frequent place to hold parties. As of Season 3, Alex holds the school passing touchdown record for a single game with 7 touchdowns, a record previously held by John Elway. His junior year he became starting quarterback. He wanted to be red shirted at first, then he saw the perks of being Blue Mountain State's starting quarterback so he decided to keep his role. After episode 4 of season 3 "The Peak" he realizes that he can go far in football. He decides that he should work towards playing in the NFL.

Radon Randell (Radon Randell (Kennedy) (Starring Season 2) : Radon was the new freshman starting quarterback from Detroit, Michigan whose talent is matched only by his outrageous behavior and huge ego. He apparently served time in prison, and once stated he played football at Rikers. Radon also has a hyperbaric chamber in his dorm room, which he uses for his own entertainment. In the 3rd season premiere, it is said that Radon has a permanent shoulder injury that will no longer allow him to play football.)

Harmon Tedesco (Cade): Harmon Tedesco is the drug-abusing kicker for the football team. Harmon exploits in anything to get him high, from smoking weed to sticking ice rods up his rectum. Harmon lives at the Goat House with Thad, Alex, and Sammy.

Denise Roy (Denise Roy (Dennis) (Starring Season 1) : Denise is Craig Shilo's high school girlfriend. A former homecoming queen and star business student at Blue Mountain State, Denise is a cold and calculating figure who only wants to marry Craig for his money, and withholds sex to make him play better, all the while sleeping around behind his back (having three-ways with two other women and sleeping with a guy from her marketing class). She was often at odds with Alex Moran, who sees through her facade.)