Haruki Nakayama is a central figure in the anime Given, serving as the bassist and de facto leader of the band. As a 22-year-old graduate student, he is the oldest member of the group, which creates a natural dynamic where he often acts as a nurturing and stabilizing presence for his younger bandmates. Standing at 178 cm tall, Haruki has a warm and approachable appearance characterized by his long light brown hair, which he typically clips back from his forehead, and his gentle brown eyes. He is originally from Miyagi Prefecture, and his family consists of his parents and two older sisters, a background that has instilled in him a strong sense of responsibility and care for others.

In terms of personality, Haruki is fundamentally kind, pure-hearted, and compassionate. He has a cheerful and easygoing disposition, often humming while he plays his bass, and he is exceptionally considerate and nurturing towards his friends. He genuinely enjoys spoiling those he cares for, particularly his bandmate Akihiko Kaji. Haruki frequently acts as the mediator during arguments, especially between the other members Ritsuka Uenoyama and Mafuyu Sato, and he diligently handles the band's online promotion and other behind-the-scenes tasks. This has led to him being regarded as the group's motherly or "big brother" figure.

Beneath this cheerful and supportive exterior, however, Haruki harbors deep-seated insecurities. He is acutely sensitive and tends to hide his true feelings of sadness, jealousy, or anger behind a casual smile, often putting the needs and harmony of the band before his own emotional well-being. His primary motivation is the success and longevity of Given. Having experienced the dissolution of previous bands, one of which ended after he dated a member and another due to internal conflicts, Haruki is determined to protect Given as a stable, familial home. He is deeply insecure about his own musical abilities, often feeling inadequate compared to the natural talents of his bandmates Ritsuka and Mafuyu. This lack of confidence is a significant internal conflict he must grapple with.

Haruki's most critical role in the story is his unrequited love for the drummer, Akihiko Kaji, a relationship that drives his personal development. He has harbored romantic feelings for Akihiko for two years, silently enduring the pain of watching him be entangled in a volatile, on-and-off relationship with the violinist Ugetsu Murata. Despite the emotional turmoil, Haruki’s loyalty never wavers. A turning point occurs when Akihiko is kicked out of his apartment and moves in with Haruki, leading to a period of cohabitation that forces both of them to confront their feelings and dysfunctions. Haruki’s patience and steady presence ultimately serve as a lifeline for Akihiko, helping him break free from his toxic cycle with Ugetsu. After Akihiko ends things with Ugetsu and dedicates himself to his violin studies, he confesses his love to Haruki, and they begin a romantic relationship, though Haruki continues to struggle with his sense of self-worth being tied to being needed by others.

Throughout the series, Haruki shows considerable development. He begins as a character who suppresses his own desires for the sake of others, but he gradually finds the courage to express his own needs. His growth is intertwined with learning to value himself, both as a musician and as a person deserving of love, not just as a supporter of his friends. As a musician, Haruki is a skilled bassist who prefers a fingerstyle playing technique. He plays a maple-colored Fender Jazz Bass and favors genres like light pop, Japanese rock, and slow-tempo dance music. Beyond playing, he is responsible for the original formation of the band, having gathered Ritsuka and Akihiko to form the instrumental group that would eventually become Given. An interesting side note is that he is a film studies major with a particular love for French New Wave cinema, and he occasionally works as a hair model for a friend.