Michie Matsumoto is the assistant band director at Kitauji High School, working alongside Noboru Taki. She enforces strict standards, particularly regarding dress code, such as requiring students to adjust shortened skirts. Her professional appearance features cropped black hair, sharp violet eyes, and consistently formal attire: a white dress shirt layered over a purple blouse, light gray capri-cut slacks, and white heels.

Her professional background includes a connection to Taki's father, Toru Taki, and Reina Kousaka's father, as all previously served as band directors at Kitauji, establishing her long-standing ties to the program. Her relationship with Noboru Taki is collegial and supportive; they spend time together outside school, like attending the Agata Festival, and she offers him subtle guidance.

Personally married with a daughter and a son, her hobbies include attending Takarazuka Revue performances. She possesses singing ability, favors the color khaki, and enjoys bamboo shoots, boiled dishes, and mizu yōkan, while disliking popcorn and peanuts.

During Kumiko Oumao's cohort graduation, she participates in planting a commemorative cherry tree for the class, observing its current small size and anticipating its growth and beauty when the students establish themselves in society. Years later, visibly moved to tears during Kitauji's national championship award ceremony, her role evolves when Kumiko Oumae returns to Kitauji as the assistant advisor, marking the continuation of her legacy within the band's leadership.