Anpanman came to life when a celestial "star of life" struck an anpan baked by Uncle Jam during his creation. This event forged his identity as a selfless hero dedicated to aiding the hungry and distressed. His head, made of anpan (red bean paste-filled bread), becomes his primary tool for assistance; he willingly offers pieces to feed others, significantly weakening himself in the process. He requires no other sustenance, drawing energy directly from the anko bean paste within his head.

He maintains a perpetually cheerful and helpful nature, driven by the intrinsic fulfillment of receiving gratitude and smiles after aiding others, a motivation rooted in an early positive experience. Possessing superhuman hearing, he detects cries for help globally and responds instantly. His key abilities include flight powered by his cape and combat techniques called An-punch and An-kick, powerful enough to shatter metal and send foes flying vast distances. He can combine these moves with allies like Shokupanman and Currypanman for enhanced Double or Triple punches.

Critical vulnerabilities center on his anpan head. Exposure to water, dirt, mold, or physical damage steadily weakens him, eventually grounding him and impairing movement. He uses a protective transparent helmet in wet conditions to mitigate this. Damage to his cape also nullifies his flight, requiring repairs by Batako-san for restoration. Only Uncle Jam baking and attaching a fresh head can fully restore him from head impairment.

His relationships define much of his existence. Uncle Jam, his creator, acts as a paternal figure, while Batako-san, involved in his upbringing, provides support like cape repairs. Cheese, a dog rescued on Anpanman's first patrol, is his loyal companion. Fellow heroes Shokupanman and Currypanman became close allies and frequent partners in justice, despite initial friction with Currypanman. He shares a protective, quasi-sibling bond with younger characters Melonpanna and Creampanda. His arch-nemesis, Baikinman, born the same day, engages him in constant conflict due to opposing morals, though Anpanman harbors no hatred and occasionally collaborates with him against larger threats. Relationships with characters like Dokin-chan remain neutral due to her disinterest, while interactions with Rollpanna fluctuate between conflict and cooperation based on her shifting alignment.

Film narratives explore his role as an aspirational figure. He mentors characters like Chapon, a mysterious boy inspired by the joy of helping others, guiding him through challenges of identity and purpose. His foundational altruism stems from creator Takashi Yanase's firsthand wartime starvation experiences, shaping Anpanman's core philosophy of combating hunger and greed through self-sacrifice. This ethos fuels his signature catchphrase, expressing renewed vigor upon receiving a new head.