Keisuke Tsukidate serves as vice-captain of the men's rhythmic gymnastics team at Soushuukan High School (Ao High), where he is a third-year student. His background includes his family managing a Shinto shrine. Tsukidate's passion for rhythmic gymnastics ignited in elementary school upon seeing team captain Masamune Shichigahama perform a backflip, prompting him to join the team alongside childhood friends Shichigahama and Nagayoshi Onagawa.

As vice-captain, Tsukidate balances the enthusiasm of the team's more free-spirited members with grounded stability, offering sensible support. Academically strong, he assists fellow third-years with their studies, especially during exam periods. His gymnastics skills make him a versatile all-rounder with few technical weaknesses, enhancing team cohesion and performance.

Beyond gymnastics and academics, Tsukidate cultivates moss bonsai, a hobby reflecting his calm and patient nature. This shared interest connects him to Kyoichi Ryugamori, a member of the rival Shiro High team. Integrating new members like Shotaro Futaba and Ryoya Misato, Tsukidate continues to provide steady guidance while adapting to the team's evolving dynamics.

Throughout the team's journey to the Inter-High competition, Tsukidate remains a consistent emotional and technical pillar, embodying reliability in both practice and pivotal performances. His development highlights themes of dedication and quiet leadership within the ensemble.