Aki has neck-length light brown hair that has fringes that part on both sides where it partially expose her forehead cyan-blue eyes that notably has very small pupils, to illustrate her exasperation around Mayumi Kurase  and she has a slim body figure with a small bust.
She is also often seen wearing a standard sailor fuku uniform.
Aki is an energetic person who is often at Mayumi Kurase's side where she encourages Mayumi to pursue her affections towards Sōma Yukihira as she knew that Sōma is her crush. However, Mayumi's indecisiveness causes her to be exasperated, and often scolds her for not being confident. However, if she pushes Mayumi to tears, she will back off and apologize.
Little is known about Aki's past, but she became close friends with Mayumi Kurase and would frequent Restaurant Yukihira after school, becoming one of its numerous regular patrons. She often observed the numerous cooking duels held between Sōma Yukihira and Jōichirō Yukihira (Sōma's father) .
Main article: Introduction Arc
In Restaurant Yukihira, Aki was part of the audience that speculated the 489th cooking duel between Sōma and Jōichirō, which resulted in the latter's victory. Afterwards, she proceeded to enjoy her meal with her friends. However, Aki scolded Sōma while consulting Mayumi, when she suffered from the aftermath of Sōma's Grilled Squid Tentacles Dressed in Peanut Butter.
The Karaage War
Main article: Karaage Wars Arc
Over the first two months Sōma spent at Tōtsuki, Aki and her friends had stopped by Restaurant Yukihira everyday. During one visit, Aki chided Mayumi for not confessing her feelings for Sōma before he left for high school. However, much to everyone's surprise, Sōma had returned home for a long weekend to air out the restaurant. During the first night of Sōma's return, Aki heard Yūya Tomita's conversation with Sōma about a Kaarage store, Mozuya that was causing financial hardships in the Sumiredōri Shopping District. When Sōma resolved to save his hometown from bankruptcy, Aki easily read through Mayumi's demeanor, to which she wanted to help Sōma, but was too shy to ask. She pushed Mayumi towards Sōma, and volunteered her as a taste tester. However, Mayumi panicked and doubted herself, then Aki punched her stomach, which quickly resolved her qualms.
- The name Aki means "overlook" (亞) (a) and "hope" (紀) (ki).
- Aki's surname Koganei means "small" (小) (ko), "money" (金) (kane/gane) and "well. mine shaft, pit" (井) (i).
- Despite being a minor character, Aki makes an appearance in the front cover of Volume 1.