Tío Jam, also known as Jam Ojīsan, is the creator of Anpanman and numerous other bread-themed heroes. His kind and warm-hearted nature consistently drives him to help others and spread happiness. Beyond his baking expertise, he demonstrates mechanical engineering skill, constructing mecha machines like the Anpanman Mobile and repairing robotic characters. Extensive travels in his youth contributed to broad knowledge, reflected in the many books within his personal library.

Visually, Tío Jam resembles Anpanman but displays distinct elderly traits: gray hair, fluffy eyebrows, a mustache, and lighter red tinting on his cheeks and nose. He is clad in a white chef's hat, white shirt and pants, a white apron, and blueish-gray shoes.

His relationships are fundamental. He created and raised Anpanman, viewing him with deep paternal affection and encouraging his best efforts and beliefs. Tío Jam extends support to other bread heroes like Shokupanman and Currypanman, though Currypanman's origin as his creation varies across media. He shares a close, familial bond with Batako; not biologically related, their mutual care runs deep, with hints they may have known each other since Batako's infancy. He maintains a paternal role toward Melonpanna, offering consistent support, and similarly encourages Creampanda's abilities as an adoptive child figure. His relationship with Rollpanna is complex due to her antagonistic blue heart; despite her rejecting invitations to join the bakery inhabitants, he retains a soft spot for her as his creation. Cheese, his pet dog, is another companion, though their bond appears less intense than his connection to Batako.

Background details confirm Tío Jam and Batako are fairies, as no humans exist in the Anpanman World. Early printed materials depicted him smoking a pipe, a characteristic discontinued in later adaptations like the television series and films. In the original 1973 picture book, he was referred to generically as "uncle" or "old man" before receiving his formal name.