Edgley was born in Perth. She is the daughter of concert and circus promoter Michael Edgley, known for bringing the Moscow State Circus to Australia during the 1980s. Her mother, Jeni Edgley, is involved in managing a 250-acre health retreat. As a child, Gigi Edgley performed both in and out of school. She also took several years of ballet, jazz, and character dance. She became mainly interested in acting and had her first professional theatrical engagement at the Twelfth Night Theater. She earned a Bachelor of Arts degree from the Queensland University of Technology in 1998. In 1999 she began acting steadily in Australia on T.V. As a believer in the school of method acting, Gigi has developed a broad set of skills and experiences for her roles. She is proficient in ballet, jazz, character dance, singing, and martial arts. Her early TV and film work included several independent productions (with later Farscape co-star Anthony Simcoe), as well a guest star spot on the popular Australian series Water Rats and a role in Australian film titled The Day of the Roses.
She is undoubtedly best known for her role as Chiana on the science fiction TV series Farscape. She originally, was hired for only one episode, and her character, was supposed to die at the end of the hour. The creators however decided to keep her around for a few more episodes. At the beginning of Season 2, she was promoted to be a regular on the show. She appeared in total of 68 episodes of the series. Her character's nickname (Pip) was actually coined by her co-star Ben Browder.
Between seasons, She has appeared in other guest starring roles on TV, including the popular internationally aired series The Lost World and BeastMaster. After the cancellation of Farscape, She pursued other projects including a role in the Australian TV drama BlackJack with Colin Friels. She has also appeared in many popular Australian TV shows such as The Secret Life of Us and Stingers.
In 2004 She reprized Her role as Chiana in the SciFi Channel miniseries Farscape: The Peacekeeper Wars.
In 2006 She starred as the female lead in critically acclaimed Australian Drama/Thriller Last Train to Freo. Her role was nominated for a Best Actress in a Lead Role by the Film Critics Circle of Australia. She also had a minor supporting role in the 2007 USA Network TV miniseries The Starter Wife. Also in 2007 and 2008 She garnered two feature length movie roles. In 07 it was a Sci-Fi movie, Showdown at Area 51, and in 08 she was back at work down under in the movie Newcastle. In 2009 She began work on the Aussie T.V. series Rescue Special Ops as Lara Knight.