Naoki Irie is the main male protagonist of the series Itazura na Kiss. He is a tall, lightly tanned young man with a slim but broad-shouldered build, gray hair, and gray eyes. He comes from a wealthy, well-educated family; his father is the president of a gaming company, his mother is Noriko Irie, and he has a younger brother named Yuuki Irie who deeply admires him. Naoki is a genius-level student with an IQ of 200, consistently ranking first in all academic subjects and excelling in sports, cooking, and any skill he attempts. Despite his remarkable abilities, he initially lacks any clear goal in life because everything comes too easily to him, leaving him feeling directionless and emotionally detached.

Naoki’s personality is outwardly cold, arrogant, and dismissive toward those he considers less intelligent. He maintains a cool, stoic demeanor and rarely shows his emotions openly. However, beneath this exterior he is actually shy and introverted, and he has difficulty connecting with others on an emotional level. His behavior toward Kotoko Aihara, the female lead, begins with blunt rejection and harsh indifference, yet he gradually warms to her as he recognizes that her persistent, clumsy efforts bring unexpected interest and change to his otherwise predictable life. His motivation evolves over the course of the story: initially, he has no reason to strive for anything beyond maintaining his perfect record, but Kotoko’s unwavering devotion inspires him to discover his own ambitions. With her encouragement, he decides to pursue a career in medicine and becomes a doctor.

Naoki’s role in the story centers on his relationship with Kotoko. He is the object of her unrequited love at the start, but as they live under the same roof due to a natural disaster that destroys Kotoko’s home, his feelings gradually deepen. He shows his affection through subtle actions rather than overt declarations, often protecting Kotoko without admitting it. Key moments in his development include kissing Kotoko while she sleeps, a gesture that signals his hidden love, and proposing marriage to her impulsively after learning that another boy is about to propose. Throughout their relationship, Naoki learns to recognize and express emotions such as jealousy, tenderness, and vulnerability, which were previously foreign to him. He becomes a devoted husband and later a father to their daughter Kotomi Irie.

Notable abilities beyond his intellect include fluency in English, exceptional cooking skills, and proficiency in tennis. He is also a quick learner, able to master any task after a single attempt. Naoki’s growth is a central arc of the series: he transforms from a detached, perfect youth into a man who faces his own feelings and life with sincerity, largely because of Kotoko’s love.