Siwon was born and raised in an affluent, strict Protestant family in Seoul, South Korea. He was scouted by a talent agent when he was 16, who recommended him to audition for the Starlight Casting System to become an entertainer. Siwon's parents disapproved him pursuing in an entertainment career, so he had to secretly audition. He successfully passed auditions, and after consideration, his parents allowed him to sign under the talent agency SM Entertainment. Siwon said that although his father allowed him to sign the contract, he would not give any help to his son. He later moved into dormitories with fellow trainees and he was trained in areas of singing, acting, and dancing. He made his first appearance in a music video of The Grace's Dana when he was still a solo singer in 2003. A year after, he made a brief appearance in the short drama, Precious Family. In 2005, Siwon made a brief appearance in the KBS drama Eighteen, Twenty-Nine as the young Kang Bong-man.
Choi Si-won (born February 10, 1987), sometimes mononymously credited as Siwon, is a Korean pop singer and actor. He is a member of super boy band Super Junior and its subgroup, Super Junior-M. Siwon is best known for his role in the 2006 Hong Kong historical action film A Battle of Wits as young Prince Liang Shi, as well as the lead male in the Korean drama Oh My Lady! opposite actress Chae Rim. Siwon can speak Korean, basic Mandarin, and very little Cantonese (Shown in his Hong Kong interview), as well as a little Japanese. He is also one of the first four Korean artists to be on Chinese postage stamps.