Principal Mita is the headmaster of Kisaragi Girls' High School and the father of Kanako Mita, a student and member of the school's baseball team. He is a middle-aged man with grey hair who serves as the school's chief administrator.

At the beginning of the story, Principal Mita is firmly opposed to the formation of the girls' baseball team. His opposition is rooted in his concern for the school's reputation, and his priorities as an administrator revolve around maintaining the school's public image rather than supporting the students' ambitions. Because of his stance, his daughter Kanako is forced to hide her involvement with the team and plays under the assumed name Tami Konaka.

Beneath his rigid and reputation-conscious manner, Principal Mita cares deeply for his daughter. This side of him becomes apparent when he considers dissolving the baseball team but decides against it on Kanako's sixteenth birthday, realizing that the team is the only place where she has found real friendship. This moment softens his earlier resistance and leads him to allow the team to continue operating.

In the story, Principal Mita functions as an authority figure whose approval determines whether the team can keep playing. His relationship with his daughter gives him a personal connection to the team and motivates his change of heart. His character development centers on learning to place his daughter's happiness ahead of his concern for appearances.

Principal Mita has no notable athletic or special abilities. His influence comes entirely from his position as principal, which gives him the power to approve, restrict, or dissolve school activities, and from his role as Kanako's father.