She is a wise second-year student who is in charge of the financial affairs. She met Yuki Ojima after bumping into him. Ever since then, they've been friends even though they are running against each other for presidency of the student council. It is shown that Shinonome has feelings for Yuki, and finds it troublesome that her older sister has feelings for Yuki too.
She is jealous of Hazuki Shinonome because Yuuki is more with her.