She has commented that she stayed "grounded" during her period as a teen star, mainly through the help of a "strong network of people" that she is close to.After The Secret World of Alex Mack ended its run, Oleynik had a starring role in the film 10 Things I Hate About You as Bianca.In March 2011, Oleynik started appearing in a recurring role on Hawaii Five-0 as CIA analyst Jenna Kaye. Oleynik appeared as the girlfriend (and later wife) of Ken Cosgrove, Cynthia Cosgrove (née Baxter), in the fourth-season episode "Chinese Wall" and the fifth-season premiere "A Little Kiss" on the AMC television show Mad Men.Plot: Adapted from William Shakespeare’s play “The Taming of the Shrew,” 10 Things I Hate About You starts off with Cameron, new student at Padua High, sitting in the office of the quirky guidance counselor Ms. He is then shown around the school by Michael, who will become his best friend. He has such good chemistry with Julia Stiles, who does the defiant and sulky teenager on point. Cameron spots Bianca Stratford (Larisa Oleynik) and her friend Chastity (Gabrielle Union) walking through the school and falls in love.The series ran on Nickelodeon from 1994 to 1998 and was one of the network's top three most watched shows, becoming quite a favorite among teen audiences and turning Oleynik into a teen idol.During the show's heyday, children who met Larisa Oleynik (and were too young to understand special effects) would often ask her to "morph" for them.After appearing in the musical, she contacted an agent and began taking acting lessons and later proved how serious she was by beginning her screen acting career at age 12, in a 1993 episode of the television series Dr.
From 1998–2000, Oleynik appeared in twenty one episodes of the NBC series 3rd Rock from the Sun as Alissa Strudwick, girlfriend of Tommy (Joseph Gordon-Levitt).
Oleynik began acting in a San Francisco broadway production of Les Misérables in 1989 after seeing an audition ad in a newspaper when she was eight years old.
She obtained two parts in the production, both with singing roles.
Later in 1993, she was subsequently cast in the lead role of the series The Secret World of Alex Mack where she portrayed a teenage girl who receives telekinetic powers as the result of an accident.
She won the role of Alex Mack over 400 other aspirants.