[3] Following three years of training, Kim debuted under the mononym Sori as one-half of the duo CocoSori with the single "Dark Circle" on January 4, 2016.
[11] Alongside former Real Girls Project groupmates Heo Young-joo, Lee Ye-eun, and Yukika Teramoto, Sori competed as one of Mol Entertainment's four representatives in JTBC's reality television competition Mix Nine, during which she became the subject of controversy following a comment made by the judge Yang Hyun-suk regarding her age and the state of her career.
[13] Sori ultimately finished in seventh place in a field of ninety-seven female contestants and therefore became a member of the resulting girl group during the final episode on January 26, 2018.
[18] Sori's debut single titled "Touch", featuring the rapper Basick, was released on September 4, 2018, in conjunction with the premiere of its music video.
[20] "Touch" was performed for the first time during its showcase held at the Dongja Art Hall in Seoul, South Korea on the day of its release.
[21] The single enjoyed minor commercial success, where its physical version debuted and peaked at number 49 on the Gaon Album Chart.
[28] Promotions for the single were held the following month due to the holiday season, which included a collaborative performance with the internet personality StarTy in Hongdae, Seoul.
[30] The fanmeet was presented by the singer Miho Miyazaki,[31] while choreographers MikuNana and former Real Girls Project groupmate Lee Su-ji appeared as guests.
[45] She subsequently performed at the series' joint concert titled "Some Days" and "Some Nights", which was held on January 18, 2020, at the Sangmyung Art Center in Hongji-dong, Jongno District.
[46] Sori made a cameo appearance as a jazz club singer in the fourth episode of OCN's action and science fiction television series Rugal, which premiered on April 5, 2020.
[47] She portrayed a fictionalized version of herself in Naver TV's romantic drama web series Almost Famous, which was based on her personal struggles.
[48][49] Prior to the development of the series, Sori quietly retired from the music industry without informing her company and fan base and was employed as a part-time barista, but she returned shortly after online petitions emerged that encouraged her to resume her career.
[49] Sori posted a promotional photo for the single, which was revealed to be titled "Initial S", to her official Twitter account on August 20, 2020.
[55] She appeared in the final episode of TVN's fantasy and historical drama Bulgasal: Immortal Souls on February 6, 2022, during which she portrayed Min Sang-woon.