Michelle Christine Trachtenberg was born in Brooklyn, NY to mother Lana, an actress and puppeteer, and father Michael, a fiber optics engineer. Of Russian Jewish and German descent, the youngster began modeling in newspaper advertisements in her home state, landing her first job at the age of three for an advertising campaign for the Kids 'R' Us chain of stores. After she watched a friend appear on a television commercial, the young actress declared to her mother that she, too, wanted to be on television. One of her first onscreen jobs was a commercial for Wisk Detergent, where she had to say the line "Wisk, wisk, wisk or tsk, tsk, tsk!" after spilling cranberry juice on her co-star. More commercial jobs followed for the future star, including campaigns with Panasonic, Fuji, Kraft, Kleenex, and Hoover. Trachtenberg eventually attended a school for gifted children in Brooklyn, until she moved to California with her mother, where she then attended Notre Dame High School in Sherman Oaks, CA.When Trachtenberg was five, she started appearing in television shows, including an uncredited appearance on a "Law and Order" (NBC, 1990-2010) episode titled "God Bless the Child," where she played a dying child. She landed a much more lighthearted role in an episode of "Clarissa Explains It All" (Nickelodeon, 1991-94), a show that starred another child actor and future teen sensation, Melissa Joan Hart. By the time she was nine, Trachtenberg was in demand for recurring roles on several television shows, and she appeared in both the soap opera "All My Children" (ABC, 1970-) as the autistic child Lily Benton Montgomery, as well as the kid-friendly program "The Adventures of Pete and Pete" (Nickelodeon, 1993-96), until she was 11 years old. As fate would have it, working on "All My Children" gave Trachtenberg the opportunity to act alongside Sarah Michelle Gellar, whom she looked up to as an actor, and would later co-star with on "Buffy."In 1996, after having had a successful career as a TV child actor, Trachtenberg got the big break she had worked very hard for when she was cast as Harriet M. Walsh in "Harriet the Spy." Over 350 girls tried out for the role, but Trachtenberg blew everyone else out of the water with her talent and similarities to the title character. "I read those books (upon which the movie was based) when I was still in the fourth grade, which was long before I was asked to be in this movie," she said. "I have always liked to spy on people, but that isn't the only thing I have in common with Harriet. I also dress like her, and I love tomato sandwiches." Comedian and talk show host Rosie O'Donnell - who played Harriet's nanny Golly - became close friends with her young co-star while working together, even taking Trachtenberg to Broadway shows - one of O'Donnell's greatest passions.After "Harriet," Trachtenberg made a return to television, with a holiday movie alongside child actor Melissa Gilbert titled "Christmas in My Hometown" (CBS, 1996), followed by appearances in the short-lived series "Meego" (CBS, 1997), the game show "Figure It Out" (Nickelodeon, 1997-99), and the educational program "Blue's Clues" (Nickelodeon, 1996-). When a 1999 feature film was made based on the popular animated series "Inspector Gadget" (1983-86) it was Trachtenberg who filled the shoes of Penny, the sidekick to actor Matthew Broderick's hilarious and dimwitted Inspector Gadget. She also had a starring role in the drama "A Father's Choice" (CBS, 2000) before scoring a breakthrough role in one of the most successful series in the history of television, "Buffy the Vampire Slayer.""Buffy" already had a cult following before Trachtenberg joined the cast in its fifth season; the actress herself was a huge fan of the show when she ran into former co-star and friend Gellar who asked Trachtenberg to come to the "Buffy" set with her so she could introduce her to the show's creator Joss Whedon. The timing could not have been more perfect, as Whedon was looking for an actress to play Buffy's younger sister Dawn, and after Gellar's recommendation, Trachtenberg read for the part, nailing it.Even while she was a regular on "Buffy," Trachtenberg kept herself busy with various other projects. She showed her comedic skills by appearing in the weekly sketch show "Mad TV" (FOX, 1995-2009) and hosted the Discovery Kids program "Truth or Scare" (2001-03). A true multi-tasker, she was tutored on set, received high marks in school, and even attended her prom, before graduating high school in 2003. She was also an active spokesperson for numerous charity organizations, including R.A.D.D., DARE America, and The Starlight Foundation. Because of her activism and involvement in anti-drug programs, Trachtenberg earned an invitation to the White House, where she helped President Bill Clinton launch The Coalition for a Drug Free America, as a representative for the country's youth.Much to the disappointment of millions of fans, "Buffy's" run ended in 2003 - when Gellar refused to sign on for an eighth season - giving Trachtenberg time to pursue film projects. Her versatility shined through in the roles she took, whether it was for mainstream movies such as the sex comedy "EuroTrip" (2004) and the heartwarming fairy tale "Ice Princess" (2005), or in edgier independent releases like the Gregg Araki-directed "Mysterious Skin" (2004) and the thrillfest, "Black Christmas" (2006). The actress also took on more complex and true-to-life characters in her small screen appearances, including a 2006 episode of "Law and Order: Criminal Intent" (NBC, 2001-), where she played a kidnapped video blogger based on the You Tube phenomenon "lonelygirl15." Trachtenberg also kept geek boys (and girls) crushing on her post-"Buffy" with appearances in music videos by bands like Fall Out Boy and Trapt.In 2008, Trachtenberg joined the cast of "Gossip Girl," another show with a cult following, as Georgina Sparks, an Upper East-Sider who had just left rehab and was set to stir things up for the lead character Serena (Blake Lively). It was rumored that the role of Georgina was originally offered to actress Mischa Barton, but Trachtenberg seemed like a natural fit for the role the minute she stepped on set. The hard-working actress also spent the beginning of the year on the set of "17 Again," a feature film starring Matthew Perry and teen hottie du jour, Zac Efron. In April 2008, she also reunited with Gellar and fellow "Buffy" alumni for a panel discussion at the William S. Paley Television Festival in Hollywood.