Noboru Taki is the music teacher and band director at Kitauji High School. He is the son of renowned band director Tooru Taki and the widower of former Kitauji band member Chihiro Taki. His musical journey started on horn in elementary school before switching to trombone in middle school. After majoring in trombone performance in college, he taught general music but avoided band directing due to tensions with his father, who previously led Kitauji's band. At age 29, he quit teaching following his wife's terminal illness and death, entering a five-year period of intense grief where he abandoned music and severed social connections. He returned to Kitauji to fulfill his wife's unrealized dream of winning a national gold medal, initially as a one-year substitute in novels but implied permanent in anime adaptations.

His personality displays duality: outwardly polite and soft-spoken in school, he becomes demanding and bluntly critical during rehearsals, prioritizing musical excellence through merit-based auditions—initially alienating students accustomed to laxer standards. Outside school, he exhibits a quieter melancholy, occasionally showing quirky hyperactivity when excited. Grief manifests in private rituals like wearing his wedding ring on his wife's death anniversary and shrine visits. He conducts without a baton as a tribute to his wife's preference. Professionally, he emphasizes student initiative and accountability, allowing self-set improvement deadlines. Despite a brass-instrument bias, he hires woodwind and percussion specialists for balanced instruction.

Key relationships shape his growth. Reconciliation with his father occurred when Tooru persuaded him to return to teaching after his hiatus. Collegiate friends Masahiro Hashimoto (percussion instructor) and Satomi Niiyama (woodwind instructor) help him reconnect with music; Hashimoto draws out his lighter side, contrasting his reserve. With colleague Michie Matsumoto, he shares mentorship and camaraderie in band discussions. Student Reina Kousaka, whose family knew his, maintains morning office visits; he misinterprets her romantic confession as gratitude. With student Kumiko Oumae, he develops a supportive dynamic, offering encouragement during setbacks and sharing personal stories—including his wife's influence during a stormy car ride in the anime.

His narrative arc shifts motivations: initially driven by personal redemption and his promise to his late wife, he gradually invests in students' growth. In novels, he feels anguish when the band wins bronze at nationals, fearing lost opportunities. Later, as third-year advisor, he delegates leadership to Kumiko and Reina, trusting them to set band goals. By the series' conclusion, his mentorship helps the band achieve national gold, fulfilling his long-term objective.