Naoki Gotoh is the father of the protagonist Hitori Gotoh and her younger sister Futari Gotoh, and the husband of Michiyo Gotoh. In his youth, during the late 1990s and early 2000s, he was an active guitarist in the Japanese indie rock scene, achieving a level of regional professional status. Although some descriptions refer to him as having been unsuccessful in his musical career, flashbacks and production material indicate that he performed and recorded at a professional level within his local scene. He has a strong personal preference for Western classic rock, particularly the work of Jimi Hendrix, and this influence is reflected in the name he gave the family dog, Jimihen.

Naoki is a kind, quiet, and supportive father who encourages his daughter Hitori’s interest in music. When Hitori expressed a desire to learn guitar, he gave her his own old electric guitar, which became her primary instrument and the foundation of her musical journey. He originally hoped that Hitori would become interested in Western music, but he happily supports her as she develops her own path with the Japanese rock-influenced Kessoku Band. His personality is gentle and approving, though his face is never fully shown in the anime or manga, keeping him as a mostly offscreen presence. His motivations are straightforward: he wants his daughter to find fulfillment through music, just as he did, and he takes quiet pride in her growing skill and dedication.

In the story, Naoki serves as a supporting character whose primary role is to provide Hitori with her first guitar and, by extension, the means to pursue her dream of playing in a band. This gift is a pivotal moment that enables her online guitarhero persona and eventually her joining Kessoku Band. Beyond this, he appears only in brief domestic scenes, often sitting at the dinner table with the family or offering an encouraging remark. His key relationships are with Hitori, whom he gently nudges toward her musical interests, and with Michiyo, with whom he shares a stable household. His connection to Futari is less explored, but he is a present and caring father to both daughters.

Naoki undergoes little to no character development over the course of the series; he remains a constant, reassuring figure in Hitori’s life. His notable ability is his past experience as a guitarist, which lends him some understanding of the technical and emotional aspects of playing live. While he no longer performs, his musical background allows him to appreciate Hitori’s progress and to offer simple but meaningful encouragement.