Jam Ojisan is the elderly fairy baker living in a forest bakery who crafted Anpanman when a shooting star animated one of his anpan loaves. This event cemented his identity as Anpanman’s creator and father figure, raising him while teaching the importance of aiding others. He radiates kindness and warmth, dedicated to supporting all residents of Anpanman World through his baking mastery and technical ingenuity. His appearance mirrors Anpanman but shows age through gray hair, fluffy eyebrows, a mustache, and lighter red tints on his cheeks and nose. He always wears a white chef's hat, shirt, pants, apron, and blueish-gray shoes.

His broad knowledge stems from extensive youthful travels, reflected in the many books lining his bakery. Beyond baking, he demonstrates mechanical aptitude by building and repairing mecha machines like the Anpanman Mobile. He maintains deep familial bonds within the bakery: treating Anpanman as his own son, offering paternal guidance to Melonpanna, and nurturing Creampanda as an adoptive child while encouraging his talents. He shares an intimate, non-familial kinship with Batako, possibly knowing her since infancy, and cares for her profoundly.

His relationship with Rollpanna remains complex due to her dual hearts; he persistently invites her to join the bakery despite her evil blue heart, showing persistent softness as her creator. He aids other bread heroes like Shokupanman and Currypanman, with conflicting lore about whether he created Currypanman. Cheese, his pet dog, serves as a loyal but less prominent companion than Batako.

Notable details include his fairy nature—humans being absent from Anpanman World—and his discontinued early depiction with a pipe. He is called "Mr. Jam" in English contexts, rides motorcycles, and holds potential undiscovered abilities as an inventor and researcher. He sustains Anpanman and allies by perpetually baking replacement heads when needed, embodying nourishment and care.