Ito was born to a Japanese father and a Korean-American mother in Los Angeles, California. She has a younger brother, Johnny. Her family later moved to Oahu, Hawaii. From a young age, Ito dreamed about becoming a singer. She was inspired by the powerful vocals of Celine Dion. At the age of fifteen, she was offered a recording contract, but turned it down. She later explained: “They saw me as a girl and not a singer.”
Initially, when Ito told her parents of plans to become a singer they disapproved of her choice. Her parents wanted Ito to attend school and meet a “nice guy”. Ito disagreed with her parents, saying they wanted to “compact her life into a storybook”. Ito graduated from McKinley High School in 2001. She moved to Japan in 2003.
In 2005, Ito was chosen to portray Reira Serizawa, the vocalist for rock band Trapnest in the film adaptation of Ai Yazawa’s popular manga series Nana. She released her debut single, “Endless Story”, under the name “Reira Starring Yuna Ito”; the song was used as one of the theme songs for the film. “Endless Story” debuted on the Oricon chart at the #2 position. Following the release of “Endless Story” was her second single, “Faith/Pureyes” (2006), which debuted at #6 on the charts.