Uncle Jam serves as the central creator and paternal figure within the Anpanman universe, responsible for bringing Anpanman to life when a star of life landed on an anpan he baked with profound care. He also created Melonpanna, Rollpanna, and potentially Currypanman, whose origins vary across media. Residing in a humanless world, he and Batako are fairies despite their human-like appearances. Uncle Jam operates a bakery that functions as a headquarters for heroes, embodying a warm-hearted dedication to spreading joy and aiding others. His extensive youthful travels endowed him with vast knowledge, evidenced by his extensive book collection and multidisciplinary expertise.

His skills encompass masterful bread-baking, exceptional mechanical aptitude—demonstrated through designing mecha like the Anpanman Mobile and repairing mechanical characters—and motorcycle proficiency. Visually, he resembles Anpanman but with aged traits: gray hair, fluffy eyebrows, a mustache, and lighter red cheek and nose tints. He consistently wears a white chef’s hat, shirt, pants, apron, and blueish-gray shoes.

Relationships anchor his role: he shares a deeply affectionate father-son bond with Anpanman, having raised and encouraged his heroism. He lives closely with Batako in a non-blood familial bond marked by mutual care. He supports Melonpanna as a father figure, shows persistent fondness for the often-antagonistic Rollpanna by inviting her to the bakery, and nurtures Creampanda’s abilities as he once did Anpanman. He maintains friendly ties with bread heroes like Shokupanman and Currypanman, offering aid when needed, and cares for his pet dog Cheese, though this bond receives less focus than his connection to Batako.

Uncle Jam appears as part of the core cast in "Soreike! Anpanman: Buruburu no Takarasagashi Daibōken!".