Hayato Sasugai is a student at Ionodai High School and the central figure of its skate-leading team. He possesses blond hair and sharp green-blue eyes, typically concealed by thick grey glasses. His standard attire consists of the Ionodai high school jacket, track pants, a blue shirt, and pale blue and white sneakers.

Intelligent, calculating, and strategic, Hayato presents an easy-going, casual facade that shifts to a serious demeanor employing underhanded tactics when he needs control. He conducts extensive research on others, using gathered knowledge to pinpoint weaknesses and suggest targeted improvements. While leveraging the Ionodai Skate-Leading team for his own objectives, he genuinely desires their success and actively aims to usurp the coaching position from Takumi Adachi.

Hayato's background revolves around his complex relationship with his older half-brother, Reo Shinozaki. They bonded over ice-skating as children, but their dynamic fractured after Hayato sustained an injury. Growing up feeling overshadowed by Reo, Hayato perceived his brother's attitude as condescending. He later embraced skate-leading as his unique pursuit—until Reo abruptly abandoned figure skating to join the same sport. This decision ignited Hayato's deep resentment, prompting him to leave home and find a team capable of defeating Reo.

Revenge against Reo fuels Hayato's relentless pursuit, driving his meticulous coaching and strategic approach within Ionodai’s team. Despite manipulative tendencies, he demonstrates authentic investment in the team's technical skills, choreography, and overall growth.

He owns a pet cat named Shiratama. He is Reo Shinozaki's half-brother, sharing the same father and being born only a day apart. Hayato dislikes carrots and often removes them from his meals. Personality assessments identify him as an ISTP, reflecting his analytical, adaptable, and reserved nature, and as an Enneagram Type 3w4 ("The Achiever"), driven by intense focus on success and validation.