Born and raised in Seoul, South Korea, Choi Seung-hyun is the great nephew of Korea’s pioneering abstract art artist Kim Whanki and grew up in contact with art due to his family. Since a young age, Choi became interested in hip hop. He and fellow future Big Bang member Kwon Ji-yong were “neighborhood friend[s] from middle school” and often danced and rapped together. Although Kwon later moved away and the two “became distant”, Choi was contacted by Kwon when YG Entertainment, Kwon’s record label, was scouting for possible candidates to create a boy group. By then, Choi had already performed on many underground stages at hip hop clubs and established a reputation as an underground rapper with the stage name Tempo. In 2003 under the name of Tempo, he was the winner of KBS Radio’s Rap Battle. After contact, Choi subsequently recorded several demos with Kwon and sent them to Yang Hyun-suk, CEO of YG Entertainment, who later asked he to audition. Choi was initially rejected by the record label, which deemed him too “chubby” to fit the “idealistic version” of an idol. He later “went home and exercised really hard because I wanted to join YG Entertainment,” losing 20 kg in 40 days. Six months later, Choi returned for another audition and was signed.

Following the release of the band’s albums and singles, T.O.P. began working on his solo career. In April 2007, he was featured with fellow Big Bang members Taeyang and G-Dragon on singer Lexy’s single “Super Fly” for her album Rush. Later that summer, he appeared as an actor in Red Roc’s “Hello” music video. He became the first member of Big Bang to venture into acting, starring in the KBS2 drama I Am Sam, portraying the school’s top fighter, Chae Musin. Despite wanting to use his stage name when acting, believing it reflects his professional side more, he is often billed with his real name, with his stage name included in parenthesis. He also became a host of MBC’s music program Music Core.

While promoting his group’s materials in 2008, T.O.P appeared on other artists’ records, including Gummy for the song “I’m Sorry” for her album Comfort, veteran singer Uhm Jung-hwa for her single “D.I.S.C.O.” and ZiA for her single “I Only See You”. The same year, he was admitted to Dankook University in the theatre department. The following year, T.O.P. portrayed the assassin Vick in the critically acclaimed Korean television drama Iris (2009). He also recorded the song “Hallelujah” for the drama’s soundtrack with Taeyang and G-Dragon. Following Iris, T.O.P. starred in the suspense film 19-Nineteen along with fellow member Seungri. The duo released the single “Because” for the movie’s soundtrack.

T.O.P’s performance the 2010 war drama 71: Into the Fire was well-received, earning him several Best New Actor awards at local award giving bodies. The movie also gained one million admissions in a week. Simultaneously, T.O.P began to prepare for his solo musical debut. During Big Bang’s Big Show Concert in January 2010, T.O.P. performed his new single “Turn It Up”. Released as a digital single, it peaked at number two, and sold over 1.3 million downloads by the end of 2010.

From 2011 to 2012, T.O.P was extensively involved with Big Bang’s promotional activities for their EPs Tonight (2011) and Alive (2012) which included a ten-month world tour that travelled to four continents. After group activities wrapped up, he focused his attention back to acting, starring in the film Commitment (2013), playing the son of a North Korean spy who is falsely accused. T.O.P first became attached to the role because he “felt sympathy for the main character, Lee Myung Hoon.” While filming a combat scene for the movie, he injured the back of his hand on a glass fragment and was later admitted to the hospital for surgery. For his role, he won the Rookie Award at the Asia Star Awards, held during the Busan International Film Festival.

In 2014, T.O.P starred in the gambling film Tazza: The Hidden Card, based on the manhwa of the same name. After debuting as a furniture designer in 2015 in collaboration with Vitra, he was awarded the Visual Culture Award at the Prudential Eye Awards. Later that year, he starred in CJ E&M’s web drama The Secret Message alongside Japanese actress Juri Ueno. Despite being a rapper, he sang on the single “Hi Haruka” as part of the drama’s soundtrack.

In August 2014, T.O.P joined the Ice Bucket Challenge, an international campaign to develop medical treatment for Lou Gehrig’s disease, also known as Amyotrophic lateral sclerosis (ALS). He made a donation to the Seungil Hope Foundation, a non-profit organization that provides aid to Lou Gehrig patients. In October 2016, in partnership with British auction house Sotheby’s, he curated a collection of contemporary art as part of a special charity auction in Hong Kong. The project was named #TTTOP, and it featured 28 works by both Asian and Western artists. The auction saw a sale of more than HK$ 135 million and a portion of the proceeds was donated to the Asian Cultural Council (ACC) to support emerging Asian artists. In March 2020, T.O.P donated 100 million won to the Hope Bridge Disaster Relief Association, which announced that it would use the donation to purchase supplies for the medical teams responsible for combating the pandemic of coronavirus outbreak (COVID-19).

T.O.P began his two-year mandatory military service on February 9, 2017, as a conscripted police officer, where he was set to be discharged on November 8, 2018, after completing the requirements. After news broke in June that he would be prosecuted without detention for use of marijuana, T.O.P was subsequently transferred to a different police division to await notice of prosecution, and was suspended from police duty pending verdict on his case. A few days after the announcement, T.O.P was found unconscious in police barracks due to a suspected anti-anxiety medicine overdose of prescribed benzodiazepine, and was hospitalized. On June 8, T.O.P’s mother confirmed that he regained consciousness and was recovering.

On June 29, at his first trial for the marijuana usage charges at the Seoul Central District Court, T.O.P pleaded guilty, admitting that he did smoke marijuana in four instances in early October 2016 and received two years of probation. After undergoing a disciplinary review by the police to decide if T.O.P should return as a conscripted policeman or complete his service as a public service officer, T.O.P was eventually assigned reservist status by the Ministry of National Defense and transferred from the police department to complete his mandatory service as a public service worker. He resumed his mandatory service as public service officer at the Yongsan Arts and Crafts Center in central Seoul on January 26, 2018. Afterwards T.O.P was discharged on July 6, 2019. His dispensation took place officially two days later.

On November 4, 2018, in celebration of his birthday, T.O.P’s fans from four Asian countries donated ₩11 million ($9,900 USD) in his name to the Yongsan Welfare Foundation to help the less fortunate.