Quinn Fabrey (Dianna Agron) is the stunning and beautiful head cheerleader of the nationally known cheerleading team "The Cherrios" at McKinley High School. Her best friends and fellow Cherrios are Santana Lopez (Naya Rivera) and Brittany Pierce (Heather Morrison). She is is part of the school's biggest "power couple" as the girlfriend of the football team's quarterback Finn Hudson (Cory Monteith) who has recently joined the glee club. Quinn is a typical "mean girl" and takes great delight in tormenting those not as popular as she is, especially Rachel Berry (Lea Michele) and the other members of the glee club, who she enjoys throwing Slushees at.
Quinn, Santana and Brittany are forced to become spies for The Cherrios coach Sue Sylvester (Jane Lynch) who wants to destroy the glee club because the Cherrios team budget has been cut to support the addition of the group. Quinn is glad of the assignment because it allows her to "keep an eye" on Finn and make sure that Rachel, who has a crush on Finn, stays away from him. The girls schedule an audition and are able to win over the glee club coach Mr. Schuester (Matthew Morrison) with a rendition of "I Say A Little Prayer For You". Mr. Schuester accepts the trio into the glee club and they begin reporting back to Coach Sylvester after each practice.
Quinn is also the president of the Christ Crusaders (also known as the Celibacy Club). This adds to the drama when it becomes known that Quinn is pregnant. She claims that Finn is the father, even though they never had sex. When he questions her, she says it is because they had made out in a hot tub and sperm "can swim". When her pregnancy begins to show, Quinn is kicked out of The Cheerios by Coach Sylvester and her popularity plummets.
When her parents discover her pregnancy, they throw her out of the house and she moves in with Finn and his mother. It is later revealed that Finn is not the father and that the baby's father is Finn's best friend and football teammate Noah "Puck" Puckerman (Mark Salling). Quinn and Finn break up and she begins a brief relationship with Puck. Having lost her position on The Cheerios and after the breakup with Finn, Quinn begins to understand what it means to be on the bottom of the social food chain.
Quinn begins to make friends within the glee club, who all support her despite her lack of popularity and pregnancy and becomes close to Mercedes Jones (Amber Riley) whom she asks to be in the delivery room with her. After giving birth to a baby girl named Beth, Quinn allows her to be adopted by Shelby Corcoran (Idina Menzel) the coach of glee club's rival, "Vocal Adrenaline".
"You used to be just sort of unlikeable, but now I feel like punching you every time you open your mouth."
"A little something something always leads to something more. I've been there. Remember?"