Goro Ooyama coaches the Meisei High School baseball team. He moved from Kyushu to Tokyo with his daughter Haruka after her junior high school graduation to accept the Meisei position, residing above a ramen shop near the school. Separated yet undivorced from his wife, the aspiring author Nagisa Tsukikage, Goro initially led the team with a reckless "just go for it" attitude.

His first year, intended as an evaluation period, unexpectedly saw the team reach the semi-finals. This outcome and Haruka's influence spurred a shift towards careful planning and strategic thinking, transforming him into a more respectable coach over time. A connection to Meisei's baseball legacy exists through his long-standing friendship with former teammate Eisuke Tachibana, dating back approximately 30 years when Goro captained the team.

Goro possesses sharp player evaluation skills. He reversed his initial plan to place first-year Toma Tachibana with other newcomers after observing his pitching, ultimately naming him ace pitcher. He also instantly recognized Soichiro Tachibana's talent as a catcher but questioned him directly about abandoning pitching. While claiming to have declined other offers to coach at Meisei, this assertion may have been exaggerated to bolster his standing. His development involves adapting his leadership, learning to balance instinct with the thoughtful analysis needed to guide the team toward their Kōshien ambitions.