Anpanman began as an anpan—a Japanese sweet red bean bread—crafted by Uncle Jam. A "star of life" struck it during baking, granting it sentience, and upon emerging, he chose his own name. His appearance features a large anpan head with a red nose, rosy cheeks, and a constant smile, clad in a red-orange uniform, brown cape, yellow gloves, boots, and a belt displaying a smiley face. The core of his head sustains him, eliminating any need for sustenance.

As a selfless hero, he aids the imperiled and hungry worldwide, leveraging super hearing to detect distress calls. Flight, enabled by his intact cape, allows swift response. His signature sacrifice involves breaking off head fragments to feed the starving, drastically weakening him. Uncle Jam must bake a replacement head to restore his strength. Environmental threats like water, dirt, mold, or head injuries impair him, requiring protective gear such as a transparent helmet in rain or water. A torn cape grounds him until Batako repairs it.

In combat, he employs "An-punch" and "An-kick," strikes forceful enough to shatter metal or launch foes great distances. He teams with allies like Currypanman and Shokupanman for combined attacks like "Double" or "Triple Punches." Despite these abilities, he embodies the "world’s weakest hero": his power stems from fragility, and heroism arises from sacrifice over invulnerability.

Relationships anchor his world. Uncle Jam and Batako serve as parental figures—creator and cape caretaker respectively. His adopted dog, Cheese, joined him after rescue and feeding during his first patrol. Key allies include the hot-tempered Currypanman and narcissistic Shokupanman, forming a core trio. Melonpanna and Creampanda see him as an elder brother, while Rollpanna shares a complex bond due to her dual-hearted nature. His arch-nemesis Baikinman, born the same day, brings persistent conflict, yet they occasionally cooperate against greater threats. Anpanman steadfastly refuses to hate foes, striving to reform them.

His ethos reflects creator Takashi Yanase’s wartime experiences with starvation and moral turmoil, inspiring a philosophy where justice means self-sacrifice to alleviate suffering—symbolized by sharing his head. Stories emphasize kindness, resilience through vulnerability, and the inherent worth of helping others, themes echoed in songs like "Anpanman March," which ponders existential purpose.