Suzu Hagimura holds the position of Student Council Treasurer at Ōsai Academy. As a first-year student beginning at age 15 and later turning 16, her youthful physical resemblance to an elementary pupil contrasts sharply with her formidable intellect—boasting an IQ of 180. She effortlessly performs 10-digit mental calculations and utilizes a photographic memory to recall entire books after minimal page-flipping. Standing precisely 140 cm (4 feet 7 1/8 inches), she reacts with intense anger to any mention of her height and privately tracks growth measurements at home.

Mentally the most mature council member, she paradoxically harbors an extreme terror of the paranormal, displaying visible distress when such topics arise. Visual gags often emphasize her stature in group scenes, using arrows or captions like "Suzu is around here." She adheres to rigid routines, including a strict 9 PM bedtime and daily naps, yet maintains environmental awareness even while asleep.

Fluent in Japanese, English, Italian, Spanish, and French, she enjoys observing others from elevated vantage points. Her relationships define key dynamics: she respects Student Council President Shino Amakusa but confronts her inappropriate conduct, tolerates Secretary Aria Shichijō’s risqué humor with visible stress, and shares a deep platonic bond with fellow first-year Vice President Takatoshi Tsuda. Their role as the council’s "sane members" fosters nonverbal communication and mutual reliance, with later narrative developments implying Suzu’s romantic interest in Takatoshi—highlighted by wistful reactions to his absence.

Beyond the council, she navigates friendships with eccentric inventor Nene Todoroki, who occasionally exhausts her, and Mutsumi Mitsuba, whom she addresses familiarly, critiques academically, yet invites to sleepovers. Her family life includes an onscreen mother, while her father remains unseen. Her name translates to "Bush Clover Village."