Amber Josephine Liu is of Chinese/Taiwanese descent, her parents are from Tainan, Republic Of China. She has one older sister named Jackie. She attended El Camino Real High School in California prior to moving to Korea to be a trainee under S.M. Entertainment.
Liu was cast from S.M. Entertainment's Los Angeles global audition in 2008, where she and one male were selected to be trainees for SM Entertainment. After a year and a half of training, she debuted under the new South Korean girl group f(x) in September 2009, labeled as "Asia's Pop Dance Group." On September 1, 2009, f(x)'s first single "LA chA TA" was digitally released. They debuted on September 2 at their very own showcase event held at the Samseong-dong Fashion Center. The group's first broadcast performance of "LA chA TA" was held at MBC's music show Show! Music Core on September 5, 2009. Months after, they released their first single album Chu~♡, consisting of three songs. On May 4, 2010, they finally released their first mini albumNu ABO.
Liu has been confirmed to be part of the new cast of the second season of Invincible Youth, a Korean variety show, in which her fellow f(x) member, Victoria, was a part of during the show's first season. Liu and Woori (from Rainbow) have been confirmed to be leaving Invincible Youth 2. Liu and Woori will be focusing on their group activities - Liu will be focusing on the Japan debut and Korean comeback and Woori will be focusing activities in Japan with her group.