Michelle Trachtenberg, who has died of as yet undisclosed causes aged 39, was an actress who found fame in Buffy the Vampire Slayer and Gossip Girl, two television series that foregrounded female power and agency; during a career that began when she was three she was equally at ease playing characters who were eccentric, troubled or just plain bad.
She joined the Buffy cast in 2000 at the start of the fifth of its seven series, remaining until the the last episode in 2003. She played Dawn, younger sister of Buffy (played by Sarah Michelle Gellar, whose own acting career had begun aged six). Though she has become biologically human, Dawn is a "key" to unlocking mystical dimensions; vulnerable and insecure, she struggles with what she knows about her origins, and goes on to suffer from kleptomania and self-harm.
"She still thinks I'm little miss nobody, just her dumb little sister," Dawn says early on. "Boy, is she in for a surprise."
Michelle Trachtenberg was at her very best in the six series of Gossip Girl (2007-12), based on the novels by Cecily von Ziegesar about a cohort of privileged students in Manhattan. She had a recurring role as Georgina Sparks, an highly intelligent but manipulative socialite given to wanton cruelty, described by one TV critic at the time as "an adolescent Cruella". It was her favourite role, she said, "because she's such an evil bitch. It's kind of easy to be evil... It's definitely a lot more fun than playing the good girl."
Michelle Christine Trachtenberg was born in New York on October 11 1985; she was the daughter of Jewish immigrants, and her mother taught her to speak Russian. She grew up in Brooklyn, though she went on to attend Notre Dame High School in Los Angeles while her acting career took off; her first job came when she was three, in a television advertisement for detergent.
In 1991 she had an uncredited bit part in the series Law & Order, but her career hits its stride when she was nine and secured a recurring role on the surreal Nickelodeon series The Adventures of Pete & Pete; between 1994 and 1996 she played the quirky Nona F Mecklenberg, best friend of one of the titular Petes (identically named brothers) who wears a cast on her unbroken arm because she enjoys scratching the itches it causes.
Her first credited big-screen role was as an 11-year-old with ambitions for a life of espionage in Harriet the Spy (1996), alongside Rosie O'Donnell. Many more roles followed, and in 1999 she played Penny, the niece of Matthew Broderick's titular superhero, in Inspector Gadget.
Following Buffy, she had a run of cameos in such series as Six Feet Under and House MD, and played a maths prodigy and aspiring figure skater in the comedy Ice Princess (2005), before joining Gossip Girl. For her portrayal of Georgina she was nominated as best TV villain at the 2012 Teen Choice Awards.
In the 2013 docudrama Killing Kennedy she played Lee Harvey Oswald's Russian wife Marina; much of her dialogue was in Russian, and her childhood lessons from her mother came in handy. In 2021 she made a brief appearance in the Gossip Girl revival, embarking on a quickly thwarted blackmail plot.
That year she was one of several actresses, including Sarah Michelle Gellar, who made allegations of inappropriate behaviour by the Buffy showrunner Joss Whedon, accusations he has denied.
Michelle Trachtenberg was highly regarded by people who had worked with her, many of whom spoke of her warmth and sensitivity. In the last year of her life she responded to comments about her gaunt and frail appearance, posting on Instagram: "I have never had plastic surgery I am happy and healthy. Check yourself haters." However, she had undergone a liver transplant a few months before her death.
Michelle Trachtenberg had been reported to be in a relationship with the talent agent Jay Cohen since 2020.
Michelle Trachtenberg, born October 11 1985, died February 26 2025