Jeeves is a significant supporting character in the anime Sister Princess, initially appearing as the trusted butler for the protagonist, Wataru Minakami. He is depicted as an elderly gentleman with a kind and dignified demeanor. His physical appearance is marked by white hair, a neat mustache, and a pair of glasses, often with his eyes shown as closed in a gentle, knowing expression. He is almost always seen dressed formally in a suit and bow tie, which underscores his professional role as a butler.

When Wataru's life is suddenly upended after he fails a high school entrance exam, it is Jeeves who facilitates the boy's departure to a mysterious place known as Promised Island, sending him to attend the Stargazer Hill Academy there. However, Jeeves' role in Wataru's life does not end with this send-off. He displays a profound and multi-faceted form of loyalty, secretly following Wataru to the island to continue watching over him. There, he adopts numerous disguises and takes on various odd jobs, appearing as an old ferryman at the dock, a teacher at the academy, a realtor, a shopkeeper, and even a doctor. Through these various personas, Jeeves is able to observe Wataru's life from a distance and ensure his well-being without directly interfering in his new relationships.

The character is defined by his quiet wisdom and unwavering faithfulness. His primary motivation is to serve and protect Wataru, not merely as an employee, but with a deep, personal investment in the young man's happiness and future. This dedication is most clearly demonstrated when Wataru is persuaded to leave Promised Island and return to Tokyo. Sensing Wataru's deepening unhappiness and misplaced sense of duty, Jeeves travels from the island to the city to visit him. He gently but firmly encourages Wataru to return to Promised Island and to the sisters who care for him, revealing that he had been watching over him the entire time. When a conflicted Wataru refuses, Jeeves, remaining the faithful servant, respectfully accepts his decision and departs, stating that he will be waiting for him back on the island. This act shows that his guidance is rooted in what he believes is best for Wataru, rather than a blind adherence to his own desires.

Jeeves' key relationship is, without question, with Wataru. He is a paternal figure, a guardian, and a confidant, representing a stable and reassuring presence in a life that has become filled with surprises and chaos. His relationship with the twelve sisters is less direct; he interacts with them primarily through his various disguises, preferring to remain in the background as a watchful guardian over the entire household. While he does not appear in the second anime series, Sister Princess RePure, his presence and influence are felt, as a picture of him is shown on the nightstand of one of the sisters, Aria, indicating he remains a cherished and remembered figure.

Throughout the story, Jeeves exhibits a notable ability for transformation and disguise, seamlessly blending into the community of Promised Island under different identities. This showcases his resourcefulness and his commitment to his self-appointed mission. Furthermore, he is shown to possess an extensive knowledge of Wataru's past and future. In the series' conclusion, Jeeves is revealed to have kept a diary that recorded every obstacle Wataru was destined to face. He ultimately discards the key to this diary, symbolizing that Wataru has grown beyond the need for such predetermined guidance and has surpassed all expectations. By disposing of the key and keeping the book only as a personal memento, Jeeves acknowledges that Wataru is now capable of forging his own future.