Kazuho Miyauchi, eldest daughter of the Miyauchi family, serves as the sole teacher at Asahigaoka Branch School, where she was once a student. She began assisting her parents with demanding rice field work during her school days and continues this labor as an adult, a primary source of her constant exhaustion.

She possesses dark violet hair, typically styled in a ponytail with side bangs. Her eyes remain perpetually closed, hiding their color. Kazuho favors plain clothing and often wears a lab coat while teaching.

Kazuho displays a markedly lazy and irresponsible nature, frequently seen sleeping or avoiding tasks. This extends to her teaching; students largely engage in self-study within the multi-grade classroom while she corrects tests or naps. Despite this, she retains some authority, occasionally scolding her sisters for misbehavior. Her agricultural work significantly deepens her lethargy.

She is the older sister of Hikage and Renge Miyauchi. Renge expresses affection for Kazuho but sometimes voices disappointment regarding her laziness. During Kazuho's university years, Renge was a baby, and in Kazuho's middle school years, she demonstrated authority over Hikage.

Her responsibilities include supervising students during extracurricular activities, a role facilitated by her status as the village adult with the most free time. She employs unconventional methods, like using a xylophone as the school bell. Kazuho also participates in community trips, such as accompanying students and villagers on the Okinawa excursion depicted in the movie.

Throughout the series, Kazuho's portrayal evolves beyond simple comic relief. While early seasons emphasize her indolence, later installments, including the film and final season, depict moments of competence and respectability, particularly during significant events or trips, highlighting underlying capability beneath her habitual tiredness.