Jenny Humphrey (Taylor Momsen) is on the outside, looking in. Daughter to rock 'n roll musician Rufus Humphrey (Matthew Settle) and younger sister to Dan Humphrey (Penn Badgley), Little J spends most of her time in Season 1 of "Gossip Girl" trying to fit in. Aspiring to be one of the "it" girls, Jenny appears to have low self esteem but gains more confidence as she battles Blair Waldorf (Leighton Meester) for the position of Queen of the Upper East Side.
Throughout the first half of Season 1, Jenny is a pawn for Blair as she tries to humiliate Serena van der Woodsen (Blake Lively). Blair loses her power when it is made public that she had a drunken affair with Chuck Bass (Ed Westwick). As one of the cool girls, Jenny believes she should have the clothes of an "it" girl. Lacking the money to buy a new dress, she steals a $15,000 dress from one of her "friend's" mother, only to realize the value of the expensive dress. Her attempt to return the dress fails as she is caught and revealed as the thief by Blair to all of her friends. In her time of need, Jenny turns to her friend, Nate Archibald (Chace Crawford) to get her back into the popular girls' good graces. After the whole ordeal, Jenny finds her supposed Prince Charming in Asher Hornsby (Jesse Swenson) but her relationship doesn't last as Blair and Eric out Asher at his party and Jenny is forced to confess that she lied about having sex with him. Abandoned once again by her friends, Jenny gives in to Blair, telling her "it's not worth it."
At the start of Season 2, Jenny interns for Eleanor Waldorf designs. Constantly harassed by Blair's friends, Jenny skips school to pursue her dream of fashion. During one of Eleanor's fashion shows, Blair attempts to sabotage Jenny by sending the models home early, but fails as Serena and her friends take the stage and turn the fashion show into a success. Rufus, now knowledgeable of Jenny's absence from school, agrees to home school her as she works. Jenny quits the internship at the suggestion of model Agnes Andrews (Willa Holland) and starts her own fashion line. She also moves out of the Humphrey's apartment and into Agnes'. The two have a disagreement about Agnes' persona and they sever their partnership with Agnes kicking Jenny out and burning her dresses. She comes back to Rufus, who refuses to let her continue, and files for emancipation. The two fix their relationship and Jenny comes home and goes back to school.
Jenny starts to date Nate but the relationship ends when he finds out that she helped in humiliating Vanessa Abrams (Jessica Szohr). She loses Nate but she climbs the social ladder to become Queen J in Season 3. Jenny meets Damien Dalgaard (Kevin Zegers) who takes her on a wild ride on the dark side. When she refuses to have sex with him, he leaves her. Jenny returns back to the fashion world and starts working with Eleanor again, but is also forced to work with Agnes, who drugs her and leaves her in a bar. Jenny is rescued by Nate and develops feelings for him again. Nate, who was dating Serena at the time, resists her attempts. Jenny tries to sabotage their relationship but fails and ends up getting kicked out of Nate's apartment, where she was staying.
At the end of Season 3, Jenny sends out a picture of Dan and Serena in bed together, almost ruining Dan and Nate's friendship and breaking up Nate and Serena. Blair tells her off and she goes running to Nate's apartment, only to find Chuck, who is heartbroken by his breakup with Blair. The two have sex, with Jenny sneaking out when Blair comes to make up with Chuck. Jenny confesses to Eric what happened, who tells Dan. Dan confronts Chuck and forces him to tell Blair what he did. Jenny is exiled, sent to live with her mother for the rest of the school year.
Jenny returns in Season 4 with Chuck's help to get an interview with Tim Gunn (himself). While there, she gets tired of her quarrels with Blair and sends Gossip Girl a text stating that Chuck took her virginity. She stays with her mom in Hudson, almost missing Lily and Rufus' anniversary, through fear of Blair's wrath. Jenny later becomes tangled in Juliet Sharp's (Katie Cassidy) scheme to get back at Serena, but when the plan lands Serena in the hospital, Jenny comes clean about what she did to Blair, obtaining her temporary forgiveness.
"He's a dog walker. I need a king, not a jester."
"Oh my God, wait; do you have a crush on me or something? Don't be embarrassed, it's totally understandable, and not that unexpected actually. I'm flattered, it's just, my heart belongs to Asher. I've gotta go, but text me, okay?"