Born on April 7, 1986, in Seoul, South Korea, Choi Si-won pursued his education at Apgujeong High School and Hyundai Senior High School before going on to study at Inha University. His professional life has taken shape within South Korea's entertainment industry, conducted primarily through the Korean language.

Choi Si-won works as a singer, songwriter, dancer, actor, and model, with his musical work situated within the K-pop genre. His roles span both the creative and performative sides of the industry: as a songwriter he participates in the making of music, while as a performer he delivers it. His work as a model extends his professional presence beyond music and acting into commercial representation, and his work as a dancer forms another strand of his performance practice.

As an actor, he holds a professional identity that runs alongside his musical output, giving him a dual presence across screen-based and musical contexts. Choi Si-won holds South Korean citizenship and has built his career within South Korea's domestic entertainment landscape while working in the Korean language. His roles as singer, songwriter, dancer, actor, and model together define him as a multi-disciplinary figure operating within the K-pop industry.