Larisa Oleynik was born in Santa Clara County, California, to Lorraine (Allen), a nurse, and Roman Oleynik, an anesthesiologist. Her father is of Ukrainian and Russian descent.
Larisa's big break came when she was eight. She had gotten the part of young Cosette in a production of "Les Misérables". Her costar was Rider Strong, playing Gavroche. The two would be reunited when Larisa guested on Rider's sitcom, Das leben und ich (1993). Larisa's most well known roles are Bianca in 10 Dinge, die ich an Dir hasse (1999), and Alex in Was ist los mit Alex Mack? (1994).