Chihiro Miura is a main character and a close friend of Mayu Morita within the high school setting of Morita-san wa Mukuchi. She is a female teenager with brown, shoulder-length hair and red eyes, often seen in her school uniform, which includes a bow and knee-high socks. Her personality is largely defined by her extroverted and energetic nature, which serves as a direct contrast to Mayu's extremely quiet and reserved demeanor.

A significant and consistent aspect of Chihiro's personality is her pronounced fondness for sweets. She is regularly seen enjoying confectioneries, with a particular visible delight for items like parfaits and strawberry shortcakes, and she often participates in sweet-centered activities with her friends. This love for sugary treats is a steady, lighthearted trait that remains a constant element of her character.

Within the story, Chihiro plays an active role in her social circle, which primarily includes Mayu, Miki Murakoshi, and Hana Matsuzaka. Her daily life is centered on navigating typical school experiences with this group, such as baking cakes, having sleepovers, visiting the library, and helping teachers with classroom duties. A key relationship dynamic involves her secret romantic feelings for their classmate Ritsuki Yamamoto, a tall, long-haired boy who is popular among the female students. This hidden affection influences some of her interactions within the group.

In her friendships, Chihiro displays a playful and sometimes blunt or tactless side. She frequently engages in teasing, particularly targeting her friend Miki, making open comments about Miki's weight or calling her ideas silly. This tendency for straightforward, and occasionally insensitive, remarks can extend to other topics, such as making comments about broken family situations that inadvertently mirror the home life of her friend Hana, who then quietly points out the similarity. Despite these moments of a sharp tongue, these shared experiences and activities help maintain her strong social bonds.

Chihiro does not undergo a dramatic transformation but develops through the reinforcing of her friendships and the navigation of her daily school life. Her notable abilities are not of a supernatural or highly skilled variety but rather social and personal traits. She is defined by her energetic and engaging presence, her established role as a lively counterpart to her quieter friends, and her capacity for both affectionate companionship and pointed, teasing honesty. One particularly endearing moment that captures her playful side shows her riding on a toy dolphin.