Akihito Fujii is Natsuo Fujii's father. His wife Jun succumbed to a terminal illness during Natsuo's youth, compelling Akihito to raise their son as a single parent. Years later, he pursued Tsukiko Tachibana—a woman noted for her "heart of ice"—with unwavering persistence until she agreed to marry him. This union established Tsukiko as Natsuo's stepmother and abruptly introduced Hina and Rui Tachibana as his stepsisters, much to Natsuo's surprise.

Akihito exhibits a tendency for unconventional choices, exemplified by his remarriage and household relocations undertaken without consulting Natsuo. Yet he maintains enduring loyalty to Jun, visiting her grave annually on the date of her passing. Visually, he embodies a middle-aged office worker archetype, frequently depicted wearing glasses.

The remarriage drastically reconfigured the family structure, integrating Tsukiko and her daughters into the Fujii home and positioning Akihito as stepfather to Hina and Rui. Professionally grounded, he remains dedicated to reconstructing a family life after loss, though his sudden decisions periodically generate tension.