Koyama began her career in television variety production in 2015 before joining Office Crescendo in 2016. After working in production management, she became an assistant producer and participated in numerous film and drama projects, particularly works directed by Yukihiko Tsutsumi.
Her major credits include the feature film First Love (2021), the Paravi drama series SPEC Saga, the TBS drama series Get Ready!, and the Netflix series Burn the House Down (2023).
Since 2023, Koyama has worked as a freelance assistant producer on projects including the Netflix series Glass Heart and the feature film Godzilla -0.0, directed by Takashi Yamazaki.
Joined THE SEVEN in January 2026.