The New York City Office of the Chief Medical Examiner has determined that actor Michelle Trachtenberg died from complications related to diabetes mellitus. She was 39.
Trachtenberg was found unresponsive in her Manhattan apartment on February 26. Emergency medical personnel arrived on the scene and pronounced her dead. Authorities reported no signs of foul play.
Initially, the medical examiner did not perform an autopsy, citing a request from the family based on religious considerations. In the absence of criminal suspicion, the office allowed the request. A final ruling was made following analysis of laboratory samples, which confirmed the cause of death.
At the time of her death, NBC News reported that Trachtenberg had recently undergone a liver transplant. The medical examiner’s statement did not mention that procedure in its ruling.
Trachtenberg began acting professionally in early childhood. Her career started with television commercials and a recurring role as Lily Montgomery on All My Children. She gained broader attention with her work on The Adventures of Pete & Pete on Nickelodeon, where she played Nona Mecklenberg. That exposure led to additional roles across children’s programming, including a hosting stint on the Discovery series Truth or Scare, which earned her a Daytime Emmy nomination.
In 1996, she starred as the lead character in Harriet the Spy, an adaptation of Louise Fitzhugh’s novel. The film marked her first major theatrical release. She later appeared in Inspector Gadget, Ice Princess, and 17 Again, among others.
Her role as Dawn Summers on Buffy the Vampire Slayer began in the show’s fifth season. As the younger sister of Buffy, played by Sarah Michelle Gellar, her character quickly became central to the plot. She remained on the series through its final season in 2003.
In 2008, Trachtenberg joined the cast of Gossip Girl on The CW as Georgina Sparks, a character who disrupted the social and romantic lives of the show’s main ensemble. She reprised the role in later seasons and appeared again in HBO Max’s revival of the series in 2021 and 2023.
Her television credits extended beyond series regular roles. She made guest appearances in episodes of House, Weeds, Sleepy Hollow, and NCIS: Los Angeles. She also voiced characters in Robot Chicken, contributing to various sketches across several seasons.
Following the news of her death, many colleagues shared tributes. Sarah Michelle Gellar wrote, “I love you. I will always love you,” alongside a quote from the Buffy series: “The hardest thing in this world, is to live in it.”
Emma Caulfield, who played Anya Jenkins on Buffy, posted, “I’m so sorry your bright light died so young. Our ‘Buffy’ family lost a little sister today … Rest in peace lovely Mish Mish. You were loved.”
James Marsters, who portrayed Spike on the same series, called Trachtenberg “a beautiful soul” and said she was “fiercely intelligent, howlingly funny and a very talented person.”
Blake Lively, who worked with Trachtenberg on Gossip Girl, also reflected on her experience. “You knew when she entered a room because the vibration changed,” she wrote. “Everything she did, she did 200%. She laughed the fullest at someone’s joke, she faced authority head on when she felt something was wrong, she cared deeply about her work and she was proud to be a part of this community and industry.”
Trachtenberg’s final screen appearance was in the 2023 Gossip Girl continuation. She had remained active in voice work and had continued to participate in reunions and fan events related to her earlier roles.