Kanae Shinjō is a second-year student at Kameido High School whose behavior and appearance consistently defy typical expectations for her age. Though a member of the school's tennis club, she rarely participates in actual tennis. Her highly eccentric and unconventional actions instead drive the group's humor.

Kanae frequently breaks social norms and defies basic physics. Examples include sleeping while standing upright with her head against a wall, wielding a tennis racket strung with her grandmother's hair, submerging into solid ground as if it were liquid, and splitting into two distinct entities. These surreal antics consistently unsettle the more conventional club member, Yuri Oshimoto, and sometimes disturb Nasuno Takamiya.

She maintains connections beyond the club, including her grandmother and acquaintances like Yucatan, who migrated from the Yucatan Peninsula. Her associates also include her cousin Mika-san, employed at a kindergarten managed by Bobby, a former United States Navy SEAL. These relationships occasionally intersect with the club's unrelated adventures, which range from visiting military bases to aiding aliens or resolving local business issues.

Her portrayal remains consistent as a source of unpredictable, physics-defying comedy across the franchise's episodes, seasons, spin-offs, and adaptations.