Kūsuke Matsuno is a student at Raimon Junior High and a member of the school's soccer club. He is frequently referred to by the nickname Max. He initially approaches the team not out of a passion for soccer but simply because he is bored and looking for something to pass the time. Endou Mamoru, the team's goalkeeper and captain, encounters him while recruiting new members, and Matsuno decides to join on a whim. His personality is marked by a restless and easily bored nature; he has tried numerous club activities before settling on soccer, as he is naturally adept at sports and tends to lose interest quickly. Despite this casual start, he discovers a genuine enjoyment for the sport and remains with the team through the Football Frontier tournament. His most recognizable physical trait is a striped plush hat with cat-like ears, which he wears at all times, including while sleeping, and it covers the upper half of his eyes. His hair is a light brown color and is tied back.

Matsuno's role in the story is that of a supporting player for Raimon. He is positioned as a forward early on and later plays as a midfielder. While he is not one of the most prominent or heavily featured characters, he contributes with his reliable all-around athletic ability. He is part of the group that faces the Aliea Academy threat and later becomes a candidate for the national team, Inazuma Japan, though he is not ultimately selected. A notable development occurs when he is temporarily turned into a member of the Dark Emperors, a team controlled by the antagonist Kageyama Reiji, where he plays as a midfielder before being freed and returning to Raimon.

In terms of key relationships, Matsuno forms a notable partnership with Handa Shin'ichi. The two develop a combination special move called Revolution V, which is empowered by the energy of an Aliea meteorite. He also participates in a three-person move called Dark Phoenix alongside Kazemaru Ichirouta and Someoka Ryuugo, also powered by the Aliea meteorite. His individual special moves include Cross Drive and Quick Draw. Matsuno's likable and easygoing personality makes him a pleasant presence in the team, but he lacks the intense drive and spotlight of the main protagonists. His motivations are simple: he seeks to avoid boredom and enjoys the camaraderie and excitement that soccer provides. He does not harbor deep personal ambitions or rivalries. His development is subtle, moving from a casual participant who joins for entertainment to a committed teammate who stays through difficult challenges.