Blair Cornelia Waldorf was born into high society on Manhattan’s Upper East Side. Her father is Harold Waldorf, and her mother is Eleanor Waldorf. She is 5’4” and slender, with beautiful brown eyes. Blair is also a hopeless romantic who idolizes Audrey Hepburn, classic movies and upscale traditions, but whose sensitive side often clashes with her tendency to be bitchy and controlling.

Blair Waldorf is vain, though her friendship with Serena van der Woodsen causes her to be insecure at times. Perhaps as a result, she has become known as Queen B - using her charm, money and social clout to win people over. Blair Waldorf’s dad, once a uptight lawyer, now lives in a French chateau with his French lover, Roman, who was a model Eleanor used to work with. He brought Roman to New York for Christmas and after some initial friction, Blair warmed up to him and they invited her to spend the summer in France. She has been through - and continues to experience the ups and downs of - a rather turbulent relationship with boyfriend Nate Archibald throughout the series, losing him to other girls several times, including Jenny Humphrey and even Serena. After an uncharacteristic night in which she performed at a burlesque club on a whim, Blair Waldorf lost her virginity to Chuck Bass, she proceeded to keep this secret affair going for a bit, but it blew up in her face and she was temporarily ousted as the school’s social queen by Jenny Humphrey. She then went back to Nate after he finally showed some gumption at the ball. This upset Chuck, who is Nate’s best friend and was starting to fall for Blair. At the end of the first season of Gossip Girl, Blair and Chuck seemed to have a good thing going, only to have him return to his womanizing ways and throw it away.

At the launch of the second season, Blair was described by creators as the queen at the center of the Gossip Girl chess game. A large portion of her story line in Season 2 revolves around her love-hate relationship with Chuck Bass, which was labeled “the heart of GG” by People magazine. While competing with Serena, Blair forms an unexpected friendship with Jenny, who states that they each work for everything they achieve, while Serena often glides through life. During their interviews at Yale University, Blair and Serena apologize for their ill feelings and resume their friendship. In the episode “O Brother, Where Bart Thou?”, Chuck is devastated by news of his father’s death, prompting Blair to offer her support while telling Chuck that she loves him. He initially shuns her advances, but later turns to her for comfort. However, the two stop seeing each other due to Chuck’s uncle, Jack Bass, convincing him he has an inability to commit to a relationship. After being rejected by Yale, Blair finds unexpected encouragement from Nate. She is later accepted into New York University, and her competitive relationship with Georgina is eventually renewed. As the season ends, Blair crowns Jenny the new queen of Constance Billard School. In the season finale, it is discovered that Blair slept with Chuck’s uncle Jack and that Chuck had slept with Vanessa Abrams. Chuck then departs for Europe. He later returns to New York and reconciles with Blair while declaring his love for her, and the two finally begin a committed relationship.

In the third season, Blair joins Vanessa, Georgina, and Jenny’s brother Dan at NYU. Much of her story line concerns her inability to attain her previous status at her new school. She finds emotional support from her mother, as well as Chuck. However, she and Chuck separate once again when Blair feels that he manipulated her while competing with his uncle. She later transfers to Columbia University, and learns that an emotionally reformed Chuck was responsible for her enrollment. They later team up as part of a role-playing scheme to help Serena’s mother and Chuck’s adopted mother, Lily. In the season finale, Chuck attempts to propose to Blair, but is interrupted by Dan, who reveals that Chuck had slept with Jenny. Two weeks later, Blair and Serena depart for Paris intending to spend the summer together.

In Season 4, Blair and Chuck become competitive once again, but eventually resume their sexual relations before recognizing their love for one another. When the relationship interferes with their business interests, she and Chuck break up once more. Chuck promises he’ll wait for her, and both affirm their belief that their love will reunite them in the end. Blair then teams up with Dan when the two share common goals. They also end up working together at W. magazine, where friction develops between the two. On Valentine’s Day, she discovers that Chuck has romantic feelings for Raina Thorpe, the daughter of his business rival. Later, she and Dan spend the evening talking on their cell phones while watching Rosemary’s Baby. Blair later quits W. and is shown asleep with Dan in his Brooklyn flat. Later, upon growing curious of their feelings for one another, Blair and Dan share a kiss before the mid-season hiatus. Blair eventually decides that she wants to be with Chuck, but shuns him once again after he tries to humiliate Dan. She is later courted by a prince from Monaco named Louis. During a private confrontation, a drunken Chuck punches a window, which cuts Blair’s face as it shatters. Afterward, Blair chooses to accept a proposal from Louis. Blair later attempts to warn Chuck about potential trouble in his family. She is then abducted by an enemy of the Basses, Raina’s father Russell Thorpe. Chuck later rescues Blair and apologizes for his violent actions. Following a night out together, the two have sex before Chuck decides that they should go their separate ways. However, the season ends with the revelation that Blair may be pregnant.

In the fifth season premiere, Blair continues to plan her wedding, but begins to encounter problems in her relationship with Louis. It is later revealed that she is pregnant. Her wedding is planned for November. Blair tells Chuck that the child is Louis’, and states that part of her wanted Chuck to be the father. Dan becomes Blair’s confidante and is shown to be in love with her, though she remains oblivious to his feelings and states that there is nothing more than friendship between them. Though she insists that she is in love with Louis, Blair begins to seek Chuck out as the season progresses. The two eventually declare their love for each other prior to an accident. The mid-season finale closes at the hospital, with Blair awake and responsive, and Chuck presumably still unconscious, suffering greater injury.