[1] As the group promoted for a year and a half, it achieved both critical and commercial success with all four of its albums topping South Korea's Gaon Album Chart and all five of its lead singles ranking in the top three of South Korea's Gaon Digital Chart.

[4] After the show,[A] Kim became a trainee under The Music Works and was selected to be one of the four members of ShelRock (셜록), a "hybrid rock" band produced by singer Baek Ji-young.

[7][8] They even made an appearance on Yang Song E's music video for her debut single "Smiling Goodbye" (웃으며 안녕).

He challenged veteran singer Yoon Do-hyun with his own rendition of YB's "Autumn Outside the Post Office" (가을 우체국 앞에서) and won, becoming the show's first winner.

[19] The following day, on August 8, it was reported that Kim signed an exclusive contract with CJ E&M to become an official artist under the company after the group's disbandment at the end of 2018.

[24] His second extended play, Moment, accompanied with the double title tracks "The Time I Need" and "Nuna", was released on December 12, 2019.

[26] On December 27, 2021, Kim released his fourth extended play The Letter, accompanied with the title track "Unforgettable".

[28][29] On July 13, 2022, Kim released "Delete", a cover of the song by Lee Seung-gi, as part of the Additional Memory Project.