Matsuri Sakuragi, known as "Mats," is an eleven-year-old girl. Her gray hair in anime adaptations appears white in the original manga. She consistently wears glasses and has large, expressive beige eyes, petite hands, and a slender, somewhat frail physique. Her typical attire includes casual dresses, shirt-and-skirt combinations, and overalls. She also wears other outfits like a school swimsuit, a kimono, or a distinctive cat hat with a bell and tail, the latter sometimes at Nobue's request. Her height matches her age and remains comparable to her friends. Her birthday is January 25 and her blood type is O.

Exceptionally shy and timid, Matsuri struggles in social situations, often needing Ana's help to speak to teachers. Her physical health is weak, making activities like swimming difficult. She frequently becomes the target of Miu's pranks and teasing, typically reacting by crying and seeking protection behind Nobue, a dynamic fueled partly by Miu's jealousy over Nobue's fondness for her. Despite this vulnerability, the manga shows her occasionally becoming defensive, slapping or shoving Miu when pranks go too far, though the anime omits this physical reaction.

Matsuri shares a classroom with Ana Coppola, forming a close friendship. She discovers Ana's hidden fluency in Japanese and her struggle with English. Matsuri actively helps Ana relearn English while collaborating to conceal Ana's Japanese abilities from classmates. She shares a significant bond with Nobue, often relying on her for comfort and security. She owns a pet ferret named John.

Within the *Encore* OVAs, Matsuri participates in the group's misadventures alongside Chika, Ana, and Miu. These include scenarios like Miu's idol aspirations leading to an encounter between realms, dealing with prank calls, and engaging in independent study sessions. Her portrayal in *Encore* remains consistent with her established traits of shyness and reliance on the group, particularly Nobue.