Konomi Fujimiya lives next door to the Koshigaya family in the rural village of Asahigaoka. A graduate of the Asahigaoka Branch School, she currently attends a nearby high school as a third-year student.

She possesses dark brown hair, typically worn in a single loose braid over her left shoulder, and purple eyes. Her hairstyle evolved from a childhood bob cut to shoulder-length hair in the manga's final chapters.

Her personality blends a caring and fun nature with a capacity for seriousness and maturity when required. She acts as a role model for younger neighbors like Komari and Natsumi Koshigaya, though a strict side emerges when angered, prompting caution.

Her relationships reflect a supportive character. She regularly visits the Koshigaya home to help Komari and Natsumi. She shares a close, sisterly bond with Renge Miyauchi and mentors her initially shy high school kohai, Akane Shinoda, helping her become more open; they play flute together in the school band. She nicknames the quiet Suguru Koshigaya "Glasses-kun".

Her abilities include persuasive skills used to correct misbehavior and musical talent as a flutist. Her consistent role involves mediating conflicts and participating in community activities, like outings with younger characters.

Trivia notes include her surname meaning "wealth, abundance", "samurai", and "temple/shrine", with "富士" referencing Mount Fuji. Her given name potentially relates to "fruit of a tree". A distinctive wardrobe feature is her yellow short-sleeve sweatshirt having removable sleeves.