Emilie de Ravin was born in Mount Eliza, Victoria, Australia. She has two older half-sisters. At the age of nine, she began studying ballet at Christa Cameron School of Ballet in Melbourne while simultaneously being homeschool by her mother. Six years later, she was accepted to the Australian Ballet School where she performed in their productions as well as Danceworld 301. However, a year later Emilie quit ballet to study acting at Australia's National Institute of Dramatic Art. Emilie's first major acting role was as Curupira, a backwards foot demon, on the Australian based television series Beastmaster. At the age of eighteen, before even having a place to live, she few out to Los Angeles and was cast in her first American acting role as Tess Harding in the teen sci-fi series Roswell. In the first season, she guest starred in several episodes, but was eventually made a series regular in the show's second season though she only returned for one episode in the show's third season. Following the end of Roswell, Emilie appeared as infamous mean girl, Chris Hargensen, in the backdoor pilot for a television series Carrie, based on a novel by Stephen King of the same name. The show was not picked up, and the pilot aired as a television movie. Over the next two years, Emilie appeared in guest spots on the shows NCIS, The Handler, and CSI: Miami.

In 2004, Emilie was cast as Claire Littleton in the ABC series Lost. She originally auditioned for the role of Shannon, speaking her dialogue with an American accent. Emilie de Ravin was working in Edmonton, so she was unable to go to the auditions, which were being held in Los Angeles. Instead, they offered her the part of Claire; she accepted without reading the script, assuming it would just be a recurring role. From a video she sent to the producers, they were able to tell de Ravin had the youth and sweetness required for the role, but also looked as though she had some life experience. The producers thought it was essential an Australian was cast for the part of Claire, as it was always planned to be a multi-cultural show, and the Oceanic 815 was leaving from Sydney. Interestingly, despite her pregnant character, Claire, having a craving for peanut butter, Emilie is allergic. She remained on the show as a series regular for the first four seasons; however, was temporarily written out of the show's fifth season. Her contract was put on hold, but she returned for the 6th and final season. In 2006, Emilie won a Screen Actor's Guild Award (along with the rest of the cast of Lost) for Outstanding Performance by an Ensemble in a Drama Series. Lost also won Outstanding Drama Series at the Primetime Emmy Awards (2005) and Best Television Series - Drama at the Golden Globes (2006) along with being nominated for countless other awards.

During her time on Lost, Emilie remained quite active with a total of nine films released over six years including indie cult classic Brick, horror remake The Hills Have Eyes, and coming of age drama Remember Me. Following Lost, Emilie took a year long hiatus from acting but returned to it in 2011 filming the Finnish romantic comedy Love and Other Troubles along with a guest appearance on Once Upon a Time as fairytale character Belle. Once Upon a Time was written and produced Edward Kitsis and Adam Horowitz former writers on the show Lost which Emilie previously co-starred. She would later act with former co-stars, Rebecca Mader and Elizabeth Mitchell. In February 2012 two weeks after her first episode of OUAT aired, Emilie was cast in the pilot Americana as Francesca Soulter. ABC subsequently decided not to pickup the primetime soap to series, and she joined the cast of OUAT as a series regular. Belle quickly became a fan favorite on the show, and grew quite a large following of new fans. She remained on Once Upon a Time until the end of its sixth season, wherein the creators of the show decided to go in a new direction and her character was written out. In the summer of 2014, while on hiatus from OUAT, Emilie shot The Submarine Kid, playing the female lead, Alice.

On 3 October 2015, Emilie announced via Twitter that she was expecting her first child, and she gave birth to her daughter, Vera Audrey de Ravin-Bilitch, in March 2016. In January 2018, Emilie became an American citizen after moving to the United States for work in 2000. She gave birth to her second child, a son named Theodore Kubrick de Ravin-Bilitch, in December 2018. In 2021, Emilie and her family relocated to Australia where she began filming the series True Colours. This Emilie's first Australian production since she moved to the states at 18 to pursue a role on Roswell. On August 25, 2023, Emilie and Eric welcomed their third child (and second daughter). They named her Alice Enid. The now family of five are still living in Australia.