|Affiliation||Kaibara Municipal High School|
|Parents||Unnamed Father & Mother|
|Manga||Another Chapter 2|
Mio is a teenage girl with a very short and petite build. She is fair-skinned, has big, dark-colored eyes, and is often seen with a bright smile on her face. She has short, light-colored hair which she ties into a braided bun at the back, with two locks of hair framing her face. She has straight, evenly-cut bangs, which covers her forehead.
Mio is a very kind-hearted, cheerful, and considerate girl. When Sawa Mitoma joined the student council, she welcomed her with open arms, and was excited for having a new member. She is also close to the rest of the student council members; Hajime, Mutsuki, and Chiaki. She also gets along with Sora and Michi, as she was invited to Michi's sukiyaki party.
While she is a bit air-headed and soft-spoken, Mio is very responsible and independent, and takes her duties as the treasurer seriously. She is helpful and always helps people out when they are in distress. She also admires Hajime for being hardworking, though she mentions that once she goes home, she never gets a chance to study.
Mio serves as the treasurer of the student council. During her debut, she warmly welcomes Sawa and reassures her that Mutsuki won't push her too much. When Michi planned to throw a sukiyaki party, Mio wanted to go but couldn't because she had other plans. She is seen helping out with the student council duties, where she acts a bit like Sawa's senior, giving her tasks and help on how to improve. She also is used to Hajime and Mutsuki's bickering, but she does not mind and rather finds it endearing and humorous, and watches over them. She spends time with the other Sohmas as well, and gets along with Sora.
- She shares the same given name as Mio Yamagishi. Whether this is a coincidence or not is unknown.