In 2019, Kōki appeared as a featured artist on Daichi Miura's song, "Katasumi", which was used as the opening theme song to the television drama Hakui no Senshi. Kōki also wrote the song. Kōki made her runway debut at the 2019 Paris Fashion Week, representing Chanel. In 2019, she appeared in the music video of the song "Eternal Love" by Kris Wu as the love interest. In 2022, she starred in the Japanese horror film Ox-Head Village.
