Choi was born on April 7, 1986 in Seoul, South Korea. He has one younger sister, Ji-won. His father was the former CEO of Boryung Medicine, a pharmaceutical company.
He later moved into dormitories with fellow trainees and was trained in areas of singing, acting, and dancing. He was featured in a music video of The Grace's Dana whilst he was being trained as a solo singer in 2003. A year after, Choi made a brief appearance in short drama, Precious Family and again in 2005 in the KBS drama Eighteen, Twenty-Nine as young Kang Bong-man, while in 2006 he played the supporting role of Park Sang-woo in drama Spring Waltz.
Choi officially debuted as part of 12-member rotational project group Super Junior 05 on 6 November 2005 on SBS's music program Popular Songs, performing their first single, "Twins (Knock Out)". Their debut album SuperJunior05 (Twins) was released a month later on 5 December 2005 and debuted at #3 on the monthly MIAK K-pop album charts.
Choi graduated from Apgu Jeong High School in February 2006 and from Inha University in February 2012 alongside fellow member Kim Ryeowook.
In 2007, Choi starred in Attack on the Pin-Up Boys along with other Super Junior members. The same year, he was cast in MBC's 2-episode mini series Legend of Hyang Dan.
In April 2008, Choi was put into seven-member sub-group Super Junior-M, a Mandopop subgroup of Super Junior for the Chinese music industry. They debuted in China at the 8th Annual Music Chart Awards, simultaneously with the release of their first music video, "U" on 8 April 2008. This was followed by the release of the debut Chinese-language studio album, Me in selected provinces in China on 23 April and 2 May in Taiwan.
After a 3-year hiatus, Choi returned to the screen with SBS' romantic comedy Oh! My Lady. The same year, he starred in the big-budget spy series Athena: Goddess of War, a spin-off to the 2009 hit drama Iris. He plays a data analyst and rookie elite agent.
Aside from being a member of Super Junior, Choi has also ventured into solo activities, mainly acting. He played lead roles in the Korean dramas Oh! My Lady (2010) and Poseidon (2011), and had supporting roles in Athena: Goddess of War (2010), The King of Dramas (2012) and She Was Pretty (2015) and Revolutionary Love (2017). Choi has also participated in various Chinese language films such as Helios, To the Fore and Dragon Blade.
Choi has joined many UNICEF campaigns since 2010. He was appointed as the special representative of the South Korea committee for UNICEF on 12 November 2015.
Upon his release from the military Choi confirmed to volunteer for a UNICEF campaign in Vietnam from August 21 to 25, 2017. The campaign is named as "SMile for U" which is a music education programme for children with disabilities conducted in partnership with Choi's agency.
