Wilson was born in Sydney, New South Wales to Karlene White and Darcy Wilson, who divorced in 1982. At a young age, she moved and lived a portion of her life in Papua New Guinea. Living there without television or radio she and her brother learned to entertain themselves putting on private shows for their parents lip synching to Liza Minnelli. This was just a hint of her budding talent to come. Her family moved around from place to place as that her father, Darcy Wilson was in the military special forces. She learned to adapt quickly to each place she moved and was very well liked.

During her teen years she involved herself in sports such as netball and swimming. As a very energetic young woman her mother was concerned about her being a tomboy and so Peta was sent to deportment classes. While there she was spotted by a modeling agent. Her new career allowed her to live in Europe but Peta had other plans.

First working as a model in Australia and Europe, she moved to Los Angeles where she studied acting in 1991. She studied with people like Arthur Mendoza from The Actors Circle Theatre in Los Angeles. As well as Tom Waits at the TomKat Repertory Group. She landed small roles in independent films such as Loser and One of Our Own. But 1996 ready to pursue her acting studies in New York she was persuaded to audition for USA network. She beat out 200 other actresses for the starring role in the Canadian television action series Nikita (U.S. title: La Femme Nikita) playing the role of Nikita, codenamed Josephine, a martial arts trained covert agent. The show was based on Nikita, a Luc Besson movie of the same name.

The show was a successful spring board for Peta's career in fact she received two Gemini nominations for Best Performance By An Actress in a Continuing Leading Dramatic Role.

In 2003, Peta Wilson appeared in the movie The League of Extraordinary Gentlemen with Sean Connery in the role of vampiress Mina Harker.