Makoto Isshiki becomes Yuuta Togashi's high school classmate and friend on their first day, bonding over mutual unfamiliarity. He sports a tanned complexion, short black hair he later shaves completely bald, and blue or grey eyes. He consistently wears the school uniform: a long black jacket with white accents, red and white tie, black pants, and brown shoes.

His defining trait is persistent pursuit of female attention. He creates attractiveness rankings of classmates and joins clubs like the Light Music Club primarily to meet girls. This motivates him to acquire a red electric guitar despite lacking skill, often leading to comedic mishaps or reprimands. Underlying loyalty surfaces in his friendship with Yuuta. Romantic feelings develop for Kumin Tsuyuri after she expresses a desire to pat his head, redirecting his romantic focus specifically toward her.

His junior high background features a disliked baseball crew cut. Paternal baldness at age 35 runs in the family, and Makoto anticipates inheriting this trait. This preoccupation manifests when he shaves his head as self-inflicted consequence after being caught conducting a "cutest girl in class" poll.

Throughout the series, he primarily offers support. Early on, he encourages Yuuta's genuine confession to Rikka Takanashi. His subplot involves joining the Light Music Club, then trying to quit, though senior members block his departure. Later appearances emphasize his shaved head and romantic misadventures for comedic effect. Relationships include a steadfast yet occasionally exasperated friendship with Yuuta and growing affection for Kumin, though this dynamic receives limited exploration beyond her influence on his actions.

His development shows minimal progression beyond initial traits. The head-shaving incident underscores his impulsive decisions regarding romance. His bond with Kumin hints at potential for deeper connection, largely unrealized in depicted events. Genetic baldness concerns and comedic mishaps persist as recurring elements.