High school and college career

Choi attended Kyungbock High School and was classmates with Lee Jong-hyun.^[2] While at Kyungbock, he, Lee and their senior Moon Seong-gon, were dubbed the "Kyungbock Trio" by rival high school teams for their well-rounded offensive capabilities.^[3] Moon and Lee went on to Korea University while Choi was recruited by Yonsei University.

During his senior year, Choi captained Yonsei to a clean sweep of the U-League regular season title and championship and the MBC Cup, the first time since 2005 Yonsei has won it.^[4][5] He was also named MVP of the MBC Cup tournament. At that time his teammates included future MVP Heo Hoon and future KBL Rookie of the Year Ahn Young-joon. He declared eligibility for the 2016 KBL draft.

Professional

Choi was considered one of the "big 3", along with Lee and Kang Sang-jae, of the 2016 KBL rookie draft and strong contenders for the first pick of the first round.^[6][7] He was drafted by Seoul SK Knights as the second pick.

After an uneventful rookie season, Choi began to grow into his role during the 2017-18 season and played a bigger role in Seoul SK Knights' second-place finish in the regular season and KBL Championship win. He averaged 9.5 points, 4.2 rebounds and 3.2 assists.^[8] After a 2018-19 season mostly plagued by injury, he returned to the side but found himself having to battle with veteran Kim Sun-hyung for a spot in the starting 5.

On December 8, 2020, it was reported that Choi had been suspended for three games by his team after he accidentally leaked a nude photograph of his teammate on his social media. He and his team immediately posted an apology, explaining that the teammate involved was also a close friend and had accepted the apology and that Choi would serve the suspension with immediate effect.^[9] The KBL further extended the suspension to five games and fined him 3 million won.^[10]

In the 2021–22 season, Choi won the KBL Most Valuable Player Award and won his second KBL championship.^[11]