Seo Ju-hyun , known professionally by her stage name Seohyun, is a South Korean singer, actress ,model, Song-writer and presenter. She is a member of South Korean girl group Girls' Generation and the leader of its subgroup TTS. Seohyun was born Seo Ju-hyun on June 28, 1991, in Seoul, South Korea, and is the only child in her family. Her mother was a chairman at a piano school and Seohyun was taught how to play piano, as well as violin and traditional Korean drums in her early childhood. She also learned horseback riding and skating as a child. Her parents did not encourage her to become a celebrity, but Seohyun credited them as the ones who helped her choose her career path by letting her experience different things.

As a fifth grader, Seohyun was discovered by a talent scout while riding in a subway train. She sang children's songs for her audition at S.M. Entertainment, and was accepted as a trainee. Seohyun cited BoA, S.E.S and Fin.K.L. as her main influences to become a singer, expressing "I thought it was cool to show and communicate the emotions through songs". In August 2007, Seohyun made her official debut as the youngest member of girl group Girls' Generation. The group gained significant popularity after the release of their hit single "Gee" in 2009. In a 2011 interview, Seohyun recalled her training days as "happy and heartwarming" memories.