Jō Jōjima, captain of Yamanami High School’s water polo club, is a third-year student whose age aligns curiously with first-year recruit Minato Kiyomizu despite their differing academic years. With a tanned complexion, burnt orange eyes, and long dusty blonde hair pulled into a restrained tie, his muscular 177-centimeter frame reflects rigorous athletic training. A boisterous and impulsive leader, he thrives on action, channeling his relentless energy into reviving the dwindling club—originally composed solely of himself—through unyielding persuasion.

His recruitment strategy pivots on leveraging Minato’s faded reputation as a former water polo prodigy, though initial interest wanes when newcomers discover Minato’s memory loss. Undeterred, Jō adapts, securing dedicated members like Yutaka Inomata and Yoshiharu Ushimado to solidify the team. His surname, Jōjima (combining "castle" and "island"), and given name, Jō ("defer" or "transfer"), subtly mirror his role as a steadfast anchor and catalyst for change.

Through setbacks and triumphs, Jō evolves from a solitary figurehead to a unifying force, embodying resilience as he cultivates camaraderie among his teammates, steadfastly shaping the club into a collective of determined athletes.