Laura Prepon was born on March 7, 1980, in Watchung, New Jersey. Her father, Michael, died in 1994. Her mother's name is Marjorie. Laura is the youngest of five children, she has a brother named Brad and three sisters: Danielle, Jocelyn, and Stephanie. She attended Watchung Hills Regional High School. She studied at the Total Theater Lab in New York City, where she appeared in numerous theatrical presentations.
She started studying acting at the young age of 15 as well as dancing ballet, jazz, and modern. She also played soccer and other sports. Before acting became her profession, she was a model, working in Paris, Milan, and elsewhere in Europe.
She's best known for her role as Donna Pinciotti in the long-running Fox situation comedy That '70s Show, for all eight seasons. She is also known for the role of Hannah Daniels on the ABC drama October Road. She has voiced characters in animated TV series such as American Dad! and King of the Hill.
She has also appeared in the Oxygen movie, Romancing the Bride. She appeared as Lauren, Mary's long lost sister, on USA network's In Plain Sight. On February 5, 2010, it was announced that Prepon signed on for Awkward Situations For Men, a pilot on ABC.
Prepon worked mainly in television, guest-starring in episodes of How I Met Your Mother, Medium, and Castle. In 2011, Prepon began filming the comedy series Are You There, Chelsea?, based on Chelsea Handler's 2008 book Are You There, Vodka? It's Me, Chelsea.