Before debuting as a member of Seventeen, Jun was a child actor who starred in multiple films including The Pye Dog (2007), for which he won the 2nd Hong Kong Film Directors' Guild's Best New Actor Silver Award, and The Legend Is Born: Ip Man (2010).

His training period involved rigorous practice and preparation, in which he developed his skills in dancing and singing.

[5] In 2018, Jun and group member The8 participated in the Chinese music reality show Chao Yin Zhan Ji (潮音战纪).

[6] Jun won the first solo stage competition on the show with his performance of "Wo Ming Bai" (我明白), a Chinese cover of Seventeen's "Thanks", for which he wrote the lyrics.

[8] On 12 August 2024, it was announced that Jun would be taking a break from group activities in South Korea in favour of acting activities in China ahead of the group's scheduled performance at Lollapalooza Berlin in early September, music show performances for the 12th mini album Spill the Feels, and the Right Here World Tour.

[9] Jun released his first solo song and special single album Can You Sit By My Side (能不能坐在我身旁), which he co-wrote lyrics for, on 14 December 2018.

[16] In China, he sold 29,000 copies of the digital album containing both tracks on QQ Music within the first week of release.

[21] Jun made an acting comeback as the male lead in the 2023 drama, Exclusive Fairytale (独家童话).

[26] On 18 January 2025, it was announced that Jun had starred in and completed work on Jackie Chan's latest film The Shadow's Edge alongside Tony Leung Ka-fai, Zhang Zifeng and Ci Sha, with Jun playing Hu Feng, one of the villainous members in the film.