Touko Usagihara is a first-year student in Class 1-3 at Roubai Girls' Academy. Her family runs a Western-style pastry shop in Tokyo; she occasionally helped with shop duties like tending the store or cleaning but initially showed no particular interest in baking. Before enrolling at Roubai, she faced significant social difficulties during elementary school in Tokyo. An unresolved disagreement with her former friend group led to exclusion and bullying. Seeking escape from this painful environment and associated rumors, she deliberately chose the distant Roubai Academy and moved into its Mangetsu Dormitory.

During class introductions, she attempted to make friends by wearing fake rabbit ears, referencing her surname "Usagihara" (meaning "rabbit field"), but this failed to resonate. As an alternative approach, she began baking snacks in the dormitory kitchen, discovering both enjoyment and talent. She became the dormitory's kitchen manager, regularly preparing popular sweets that won over residents. This role required navigating strict dormitory rules, including submitting formal requests for ingredient purchases. Her baking skills contrast her academic struggles and poor grades.

Touko maintains an energetic, mischievous, and talkative demeanor, often engaging in gossip and organizing surprises. This cheerful exterior partially conceals lingering sensitivity about her past and a tendency to hide vulnerable feelings. She shares her dorm room with Neko Kamimoku and is on casual, first-name terms with Ai Tatsumori due to shared cram school attendance. Her friendship with Komichi Akebi developed quickly through adjacent seating. During a summer trip to Tokyo with Komichi, Erika Kizaki, and Ai Tatsumori, an encounter with a former classmate who participated in her bullying prompted her to reveal her painful history. Komichi later reassured her, comparing her choice to leave Tokyo to a salmon swimming upstream and affirming her courage. After this trip, Komichi and Erika began addressing her by her first name "Touko," signifying deepened trust.

She is an active member of the school's softball club and enthusiastically attempted to recruit Komichi, declaring ambitions to reach national competitions. Her athletic involvement sometimes leads to mishaps, like accidentally hitting a softball into mud that soiled Komichi's uniform, prompting her to take responsibility by cleaning it. While generally sociable, she occasionally exhibits social awkwardness, exemplified by an impulsive joke about swapping clothes with Komichi that led to a brief, awkward situation. She manages her anxieties through baking and maintains her role as the dormitory's primary provider of snacks.