Uncle Jam, also known as Jamu Ojisan or Mr. Jam, is the creator and paternal figure of Anpanman. He brought Anpanman to life after a shooting star landed in his oven during an anpan baking session, marking Anpanman's birth and establishing Uncle Jam's foundational role in the series' lore. Depicted as elderly and kind-hearted, he resides in a bakery as a baker and inventor. His appearance features gray hair, fluffy eyebrows, a mustache, and light red tinting on his cheeks and nose. He consistently wears a white chef's hat, shirt, pants, apron, and blueish-gray shoes.

His personality embodies warmth, wisdom, and selflessness. Extensive travels in his youth contributed to vast knowledge, reflected in his bookshelf-filled room. He prioritizes helping others by baking bread, repairing damaged hero capes, or constructing mecha machines like the Anpanman Mobile. His mechanical expertise also extends to fixing robotic characters, underscoring his versatility as both a craftsman and problem-solver.

Relationships are central to his character. He raised Anpanman like a son, encouraging him to pursue justice and aid those in need. This paternal dynamic extends to other characters he created or mentors: Currypanman (whom he explicitly made in early manga and anime episodes), Melonpanna (treated as a daughter figure), and Creampanda (an adoptive child he supports). He maintains a familial bond with Batako, his bakery assistant; though unrelated, their closeness is likened to family, with implications of knowing her since infancy. His interactions with Rollpanna reveal a persistent hope for her redemption, often inviting her to join the bakery's inhabitants despite her antagonistic tendencies.

His background includes scrapped elements like smoking a pipe in the original manga, omitted in later adaptations. Notably, he and Batako are identified as fairies, as humans do not exist in the Anpanman World. His conceptualization by series creator Takashi Yanase draws from Yanase's wartime starvation experiences, positioning Uncle Jam as a symbol of sustenance and resilience. This thematic role manifests in his ongoing mission to nourish and protect, reinforcing the series' emphasis on communal care.

Across all media, including films like *Kirameke! Ice no Kuni no Vanilla-hime*, Uncle Jam remains a stabilizing force. He provides new heads for Anpanman when weakened and supports allies against threats like Baikinman. His absence or incapacitation often heightens narrative stakes, highlighting his indispensable role as the franchise's moral and logistical anchor.