Gossip Girl features ensemble cast of nine regular speaking roles which were mainly adapted from the book series. The first few episodes of the first season included the original concept from the books, mainly following the lives of the five teenage characters in their high school years. Serena van der Woodsen (Blake Lively), is the protagonist of the show, she is very attractive, but also vulnerable, often described as an 'it girl'. It is revealed that she has had a scandalous past, that continues to haunt her, she is known for her many off-again relationships with the male characters and is known for rebellious drive outs. Dan Humphrey (Penn Badgley), an outsider who becomes a part of the turbulent Manhattan scene, an aspiring writer and fairly straight-arrow guy with a good heart and morals. In the third season he begins to date a famous movie star which leads him to realize that he is in love with his childhood love, Vanessa. Blair Waldorf (Leighton Meester) is a beautiful Queen Bee of Manhattan's social scene, as well as Serena's best friend and occasional rival. After realizing that Nate Archibald is just her perfect boyfriend she pursues a relationship with Chuck Bass. Nate Archibald (Chace Crawford) is a wealthy guy, and the perfect "Golden Boy" of the Upper East Side, always being fought over by the prominent female characters. Chuck Bass (Ed Westwick) serves as the show's antihero, being a womanizer and party lover with a troubled life and past, but possessing a soft side to him as well.
Beside the five regulars mentioned above, three more characters appeared in the pilot episode. Jenny Humphrey (Taylor Momsen) is Dan's younger sister, who desperately tries to become the next Queen Bee, a goal that makes her realize the true values of life; Lily van der Woodsen (Kelly Rutherford) and Dan's father Rufus Humphrey (Matthew Settle), both of whom share a romantic past which follows them throughout the show, and eventually leads to marriage.
Vanessa Abrams (Jessica Szohr), enters the show in its first season as Dan's past love, and becomes a series regular after the 14th episode. Other characters include Eric van der Woodsen (Connor Paolo) Serena's overly caring gay brother, who becomes very close with Jenny, but ultimately schemes against her, Georgina Sparks (Michelle Trachtenberg), the main antagonist in the show, with a recurring role and Carter Baizen (Sebastian Stan), Chuck's enemy and love with Serena.
In addition of the characters mentioned above lot of characters have guest starred as their parents and other relatives. Eleanor Waldorf-Rose (Margaret Colin) and Harold Waldorf (John Shea) appeared as Blair's divorced parents, with Cyrus Rose (Wallace Shawn) as Eleanor's husband and Blair's stepfather. Dorota Kishlovsky (Zuzanna Szadkowski) plays Blair's loyal maid. Anne Archibald (Francie Swift) and Howard "The Captain" Archibald (Sam Robards) appear as Nate's estranged parents. While William van der Bilt I (James Naughton) and William "Tripp" van der Bilt III (Aaron Tveit) play Nate's manipulative grandfather and cousin, respectively. Bartholomew "Bart" Bass (Robert John Burke) has appeared as Lily's ex-husband and Chuck's demanding father. Celia "CeCe" Rhodes (Caroline Lagerfelt) appears as Serena's grandmother and Gabriela Abrams (Gina Torres) as Vanessa's mother.