Cilmi was born on October 10, 1991 in the Melbourne suburb of Dandenong. She lives with her parents Paula and Joe (Italian-Australians whose origins are in Calabria, Italy) and her brother Joseph. She attended Sacred Heart Girls' College, but now continues her education via correspondence.At an early age she developed an interest in a wide range of musical styles, including Nina Simone, Led Zeppelin, Janis Joplin, The Sweet, T.Rex and Cat Stevens. Despite her natural aptitude and vocal talent, she was told that she lacked the discipline necessary to pursue a singing career. Idolising Janis Joplin, during this time she sang with a band performing cover songs by Led Zeppelin, Jet, Silverchair and others.Cilmi recorded original songs with writer/producers Barbara and Adrian Hannan of The SongStore.In 2004, she captured the attention of Michael Parisi, a record company executive from Warner Music, while giving an impromptu rendition of the Rolling Stones' song "Jumping Jack Flash" at the Lygon Street Festa, a community festival in Melbourne. At the age of thirteen, Cilmi travelled to the US and UK with Adrian Hannan and was offered four major US deals. She eventually signed a contract with Island Records UK.