Tsuyoshi Nakanojou is a 15-year-old student in class 1-Q at Tokisadame High School. He possesses a distinctive natural mohawk, with yellow hair growing only along the center of his scalp while the sides are bald. This unique hair trait is inherited from his father. Attempts to alter his hairstyle fail, as it always reverts to its natural state. His eyes are typically drawn as simple straight lines. He wears the standard black school uniform regularly, opting for casual t-shirts at home or outside school hours.

Despite an appearance suggesting a delinquent persona, Nakanojou exhibits a kind and gentle nature, demonstrated by actions like diligently watering flowers. He consistently uses honorifics when addressing others. Aspiring to be a scientist, he maintains a rational worldview and firmly rejects supernatural beliefs, actively investigating phenomena like ghosts to disprove them, even visiting locations such as Osorezan seeking mediums.

His relationships involve recurring comedic situations. He frequently becomes an unintended victim of Kana Nakamura's mishaps, particularly her attempts to capture Nano Shinonome, resulting once in his mohawk being shaved off. He remained bald until an accidental application of Principal Shinonome's hair grower caused rapid regrowth. He shares a friendship with Tanaka, another student with unconventional hair. Weboshii developed a brief romantic interest in him, primarily due to his mohawk, but this ended abruptly after Nakamura shaved his head. A significant misunderstanding arose when Tanaka mistakenly believed Nakanojou and Haruna Annaka were dating, escalating when Nakanojou received an unsigned love letter he initially attributed to Annaka, later clarified as another misunderstanding.

The etymology of his name reflects certain traits: "Tsuyoshi" (剛) translates to "sturdy," "strength," or "tough," while his surname "Nakanojou" combines characters for "middle" (中), "this" (之), and "article" (条). His birthday is May 21.