He made his solo debut on June 3, 2019 with the single "Good Night".
2018–2019: Under Nineteen
On January 26, 2019, during the thirteenth episode, it was announced that he had departed from the show due to health reasons. It was revealed in the show that he was suffering from temporomandibular joint dysfunction, which made it difficult for him to speak.
- Half/Half (2020)
- "Good Night" (2019)
- "Tell Me, It's Not True" (2019)
- "Pretend You're All Right" (2019)
- "Here" (2020)
- "Good Morning" (2020)
- "My Dear" (2019)
- Under Nineteen (MBC, 2019) - contestant
- He is the first artist under Black Y Music
- He enjoys playing the guitar
- His specialty is badminton
- His favourite food is chicken
- His favourite song is Cold Water - Major Lazer (Feat. Justin Bieber and MØ)
- He received his nickname 'Little Crush' whilst participating on Under Nineteen due to having incredible vocals like Crush
- On January 26, 2019 it was announced that he would leave the show due to health reasons
- Prior to his debut, Jinseok held mini fan meet ups in both Korea and Japan, as well as attending Korea's Spring Fashion week 2019.
- Black Y Music