Kanon Matsubara is a first-year Literature student at Keihou Women's University. She attended high school at an unspecified institution, starting in class 2-A before advancing to class 3-A. In high school, she first joined the tea ceremony club and later a band. She possesses long, curly pale blue hair usually worn loose with a section pulled into a side ponytail fastened by a ribbon, violet eyes, and stands 156 cm tall. Her casual style favors frilly, feminine clothing: light blue off-the-shoulder dresses with ribbons and transparent frills, fuzzy cream jackets with patterned dresses in winter, and baby pink T-shirts with checkered gray skirtalls in summer. She always wears a red heart necklace.

Kanon exhibits a shy, nervous, and easily overwhelmed personality, often expressing distress with "fuee." She is clumsy, becomes a nervous wreck quickly, and struggles to refuse requests, making her susceptible to others' affairs. She has a terrible sense of direction, getting lost even in familiar places and struggling with public transport, though she can find cafes and shops by smell. Despite this, she demonstrates sensible, responsible qualities, acting as one of the more level-headed members in her band. She balances her anxiety with kindness, politeness, and a strong work ethic. Over time, she develops greater courage and determination, challenging herself with activities like solo street performances. Her hobbies include watching jellyfish, visiting cafes, drawing, creating felt dolls after learning from a bandmate, and cooking meals for her shared apartment.

Her background includes nearly quitting drumming before Kokoro Tsurumaki recruited her into Hello, Happy World! as drummer. Though her involvement was initially accidental, she gradually embraced the role, contributing rhythmic skills despite frequently breaking drumsticks due to clumsiness. Within the band, she collaborates closely with Misaki Okusawa to manage the group's unconventional activities and wild ideas, serving as a stabilizing influence alongside Misaki. She draws inspiration from Kokoro's bold spirit and ability to unite people. Kanon is the only band member aware of Misaki's dual role as the DJ mascot Michelle. Outside the band, she shares an apartment and maintains a longstanding friendship with Chisato Shirasagi, known since middle school. She holds a part-time job at a fast-food restaurant alongside Aya Maruyama. When lost, she relies on friends like Chisato, Kaoru Seta, Hagumi Kitazawa, or Misaki for help, with Hagumi and Kaoru frequently finding her.

Kanon's development shows significant growth from a hesitant, withdrawn individual to someone more assertive and courageous, stemming from band experiences and the positive impact of making others smile through performances. Events like the Detective Kokoro story highlight her evolving helpfulness and problem-solving abilities. Though still prone to anxiety, she learns to voice opinions and handle high-pressure situations with unexpected calmness, noted by Kokoro. She has drawn since childhood, often indoors with her younger brother, and experiments with new recipes. She dislikes mushrooms but enjoys sweets, cakes, coffee, and tea. Trivia includes her nickname "Jellyfish of the Labyrinth," her resemblance to the fictional princess Nicolina of Happinelle Kingdom, and cameo design inspirations during collaborations like Ojamajo Doremi and Re:Zero.