Shigeru Fujiwara is a middle-aged man with short black-gray hair and eyes, sporting rectangular glasses and stubble. He typically wears long-sleeved shirts and pants and is often seen reading a newspaper at home. He and his wife, Touko Fujiwara, are distant relatives of Takashi Natsume. They fostered him after Shigeru encountered him at a family funeral, noticing his loneliness and difficult circumstances. They invited Natsume to live with them in their countryside home, striving to create a supportive family environment. Aware that Natsume keeps aspects of his life private, they consciously avoid prying, emphasizing their home is his sanctuary regardless of any disruptions.

Shigeru is soft-spoken, serious, and kind, possessing a warm sense of humor that emerges as Natsume grows comfortable. He actively encourages Natsume to feel at ease, expressing approval when Natsume behaves spontaneously or openly, contrasting with Touko's occasional worry. He reassures Natsume during incidents like accidental property damage, dismissing apologies with reminders that the home belongs to him too. His hobbies include pottery, a passion he shares with Natsume by involving him in acquiring pieces and attending classes.

As the only child of the Fujiwara family, Shigeru grew up in a multigenerational household in the same town he now resides in. His childhood featured a large circle of friends and a brief but significant friendship with Reiko Natsume. During this time, his family's home was haunted by a malicious ayakashi named Karime. Reiko intervened to exorcise the spirit, causing substantial damage to one room—the same room later occupied by Natsume. Shigeru was reprimanded by his parents for the destruction, and afterward, he and Reiko never spoke again. Over time, he forgot her name and face, recalling her only as a beautiful, capricious girl. He attended college, living independently and learning to cook. His parents and grandparents likely passed away before his adulthood, though the circumstances remain unconfirmed. He married Touko in his twenties or late twenties, and they moved into the ancestral Fujiwara house. Unable to have children, they later decided to foster Natsume.

Shigeru maintains a loving and comfortable relationship with Touko, reflecting mutual affection and reliance. He interacts warmly but sparingly with the yokai Madara, who resides with them in the form of a cat known as Nyanko-sensei. His forgotten connection to Reiko indirectly shapes his empathetic approach to Natsume's struggles, though he remains unaware of their familial link or her role in his childhood.