Makoto, also referred to as Mako-chan, is an elementary school student who attends class five-two and is a classmate of Chiaki Minami. He is a supporting character in the series who becomes a frequent visitor to the Minami household. His physical appearance is that of a young boy with short brown hair and brown eyes.

His background begins when he first visits the Minami home alongside classmates to work on homework. Upon meeting the eldest sister, Haruka Minami, he develops an immediate and intense crush on her, so much so that he abandons his homework to help her in the kitchen. This act of helping Haruka cook dinner sparks jealousy and anger from Chiaki, who becomes uncomfortable with his attention toward her older sister and threatens to ban him from the house.

In order to continue seeing Haruka without Chiaki's detection, Makoto is forced by Kana Minami to cross-dress. In this female disguise, he is referred to as Mako-chan. Kana presents this disguised version as her junior, allowing him to enter the home without arousing Chiaki's suspicion. Over time, Makoto appears to both struggle with and develop a certain enjoyment of the cross-dressing role, sometimes proclaiming that women's clothing cannot contain his wildness as a man while simultaneously appearing to glow in typically feminine style. Despite the incongruity, his discomfort while in disguise remains minimal, as his identity as a young elementary school student makes the deception relatively easy to maintain.

Personality-wise, Makoto is not known for good judgment. He is simple, impulsive, and easily swept along by the schemes of others, particularly Kana, who often takes advantage of his naive and trusting nature. His classmates and Chiaki consider him an idiot, and Chiaki has nicknamed him idiotic child, a label that his peers feel is more of an accurate impression than a mere nickname. He is prone to acting without thinking, which frequently leads to comedic situations. His awkward sincerity, however, makes him memorable despite his lack of sharpness.

His primary motivation is his infatuation with Haruka. This crush drives much of his behavior, from his willingness to cross-dress to his eagerness to spend time at the Minami residence. He is also motivated by a desire for companionship and a tendency to follow along with whatever activity is presented to him.

In terms of his role in the story, Makoto serves as a source of comedy through his earnest yet foolish actions, his cross-dressing alter ego, and his interactions with the three Minami sisters. His relationship with Chiaki is defined by her disdain for his foolishness and her protectiveness over Haruka. His relationship with Kana is one of manipulation on her part, as she orchestrates his disguise and drags him into various antics. His relationship with Haruka is one of unrequited admiration, as she treats him kindly but is largely oblivious to the depth of his feelings. Among his classmates, he is seen as the idiotic child and is often the butt of jokes.

Over the course of the series, Makoto shows some development in that he becomes more accustomed to his dual identity as himself and as Mako-chan. He grows less awkward in the female role and continues to be a recurring presence in the Minami family's daily life, though his core personality of being simple, impulsive, and easily led remains consistent. His notable abilities include a surprising commitment to his cross-dressing persona and a willingness to embarrass himself in pursuit of his goals, as well as a capacity for sincere, if clumsy, acts of kindness.