Born in 2000 during the Year of the Dragon, Nanami Hiyoshi is a 16-year-old student at Numazu Minami High School and a member of its archery club. She stands 145 cm tall, weighs 38 kg, and has blood type A. Her cool and objective personality contrasts with her appearance. As an only child, she regards her cousin Fuuka Torimi as an older sister figure. Nanami enjoys watching anime, hand-making items, remaking old clothes, drawing, and design. She is associated with a PAS VIENTA5 bicycle.

Categorized as a minor character in the franchise, she appears alongside Fuuka Torimi in the spin-off "Four Seasons: Fuuka to Nanami," which highlights seasonal changes and the joys of motorcycling. Her narrative role in this spin-off emphasizes experiential moments over significant character development. Her physical design includes a ponytail hairstyle.