Izumi Shinohara is an 18-year-old high school senior with a slim physique and height of 150 cm. Her pale complexion contrasts with short black hair styled with spiky bangs and blue, drooping tareme eyes. She possesses medium-sized breasts.

Hailing from a wealthy family, she attends the protagonist's school and practices traditional Japanese archery as a kyudo club member. Her wardrobe blends traditional and contemporary elements, frequently featuring hakama, haori, yukata, keikogi, school uniforms, beanies, scarves, vests, coats, trousers, formal shirts, neckties, bow ties, and cuffs. She typically carries a bag.

Izumi exhibits tomboyish mannerisms through masculine speech patterns, using "watashi" as her personal pronoun while maintaining a blunt and occasionally rough demeanor that invites teasing from others. Her activities include skiing.

She shares a close friendship with Tomomi Mizuno, the protagonist's childhood friend. The narrative establishes mutual exclusivity in romantic possibilities: the protagonist cannot simultaneously pursue relationships with both Izumi and Tomomi, making pursuit of Izumi require distancing from Tomomi.

Within the "Dōkyūsei 2 Special: Sotsugyōsei" OVA, Izumi appears as a minor character portrayed consistently with her original visual novel traits.