Chitose Hitotose is the central male protagonist of Happy Lesson, a high school student whose life is defined by a profound sense of loss that gradually transforms into an unconventional but meaningful family bond. He is an orphan who lost his parents in an accident when he was young, an event that forced him to grow up in an orphanage. This background left him a solitary and troubled individual, and by the time he enters high school and moves back into the large house his parents left behind, he has developed a reputation as a delinquent, prone to fighting and keeping others at a distance. Despite his standoffish and proud exterior, Chitose is not inherently malicious; his isolation is a shield born from his past pain. Underneath, he possesses a strong sense of determination and a willingness to help those he cares about, which becomes more evident as the series progresses.

Chitose's motivations are largely reactive at the start, focused on simply surviving his circumstances. However, his entire trajectory changes when his five female teachers, noticing his failing grades and difficult life, take it upon themselves to move into his house and act as his mothers. His initial role in the story is that of a reluctant participant in this chaotic arrangement, often finding himself the bewildered and exhausted victim of his new mothers' overbearing and eccentric methods of parenting. From being force-fed study sessions to becoming a test subject for a chemistry teacher's bizarre experiments, Chitose endures a constant stream of domestic turmoil, often relegated to sleeping on the couch since his teachers occupy all the bedrooms. His role is to be the emotional core and straight man to the antics of the five mothers, and through him, the story explores themes of healing, found family, and personal growth. As the series continues, his role shifts from passive sufferer to an active participant who genuinely comes to value the chaotic love surrounding him.

Key relationships define Chitose’s development. His bond with his five teachers, particularly Mutsuki Ichimonji who acts as the de facto head mother, is the central axis of the series. While he initially resents their intrusion, he slowly learns to accept their maternal affection, leading to a genuine familial bond. He also shares a close, non-blood-related sibling relationship with Minazuki and Hazuki, two girls he met and befriended at the orphanage. Minazuki acts as a younger sister who deeply adores him, while Hazuki is an older sister figure and a famous pop star who cares for him deeply. Other significant relationships include his childhood friend Kanna, who has a crush on him, and his class representative Fumitsuki, whose romantic feelings for him he remains completely oblivious to. A major rival appears in the form of Nagatsuki Kuron, a girl who also sees Mutsuki as a mother figure and constantly challenges Chitose, leading to numerous physical confrontations. Interestingly, they share a common ground in their past loss and impressive fighting abilities.

Throughout the series, Chitose undergoes significant character development. He begins as a hostile and untrusting delinquent, a classic example of a student with a painful past acting out against a world that has hurt him. The interference of his five mothers, which he initially sees as a nuisance, gradually chips away at his defenses. Their persistent, if often misguided, care forces him to confront his own loneliness and slowly reintegrates him into a functional family structure. This positive influence helps him become a more well-adjusted and open person, moving from a solitary fighter to a young man who understands the value of having people to come home to. By the final stages of the story, his journey from an angry orphan to a loved son is complete, albeit leading to an unusual resolution where the nature of his relationships with his mothers is transformed.

In terms of notable abilities, Chitose is an exceptionally skilled fighter. From the very beginning, he is shown easily defeating multiple bullies who mock him for his lack of parents, establishing his physical prowess. This fighting ability becomes particularly prominent during his ongoing conflicts with the equally skilled Nagatsuki, where he is able to hold his own and even outlast her by dodging her attacks. Complementing his combat skills is an incredible physical resilience; he demonstrates a made of iron quality, withstanding a great deal of physical punishment and bizarre experiments from his mothers, including having his pain tolerance tested to the point of injury, yet he consistently bounces back with little lasting harm. These abilities, born from a life of hardship, become tools for survival and, later, for protecting the eccentric family he comes to cherish.