Keisuke Tsukidate is a third-year student at Ao High School and vice-captain of the men's rhythmic gymnastics team. A founding member alongside childhood friends Masamune Shichigahama and Nagayoshi Onagawa, their bond stretches back to elementary school. His family's management of a Shinto shrine imbues him with calm composure.

Tsukidate acts as the team's sensible anchor, offering steady support to more free-spirited teammates. He provides gentle guidance and encouragement, prioritizing stability over strict authority. Academically strong, he excels without midterm worries and regularly tutors peers.

As a gymnast, he is a reliable all-rounder with minimal weaknesses, contributing crucial balance. His technical skill and consistency make him a dependable performer. He cultivates tranquil moss bonsai, reflecting his appreciation for nature and patience. This hobby fosters a friendship with Shiro High's Kyoichi Ryugamori, who shares his plant appreciation.

His focus is unwavering support for the team's growth, especially during Inter-High preparations. His leadership complements the captain's enthusiasm through behind-the-scenes reinforcement. He joined the team after witnessing Shichigahama's inspiring backflip, cementing their camaraderie.

His role remains consistently supportive throughout the narrative, without significant personal evolution or conflicts. His enduring relationships with Shichigahama and Onagawa highlight themes of loyalty and shared history, dynamics which remain stable.