Originating when a life star landed on an anpan baked by Uncle Jam, Anpanman was raised from infancy by Uncle Jam alongside Batako. His physical form features a large anpan (red bean paste-filled bread) head distinguished by a red nose and rosy cheeks. He wears a red-orange uniform, yellow gloves, boots, and belt, complemented by a brown cape and a smiley face symbol on his chest. The tsubu-an (whole bean paste) filling inside his head acts as his sole energy source, eliminating his need for conventional food or drink; he sustains himself by absorbing energy directly from this bean paste. Water, dirt, mold, or physical damage to his head significantly weaken him, impairing flight and movement, prompting him to wear a transparent helmet in wet conditions. A torn cape also disables his flight until Batako repairs it. When damaged or consumed, Uncle Jam bakes him a new head for regeneration, with the old head discarded afterward. His signature An-punch and An-kick deliver immense force, capable of shattering metal or launching heavy objects. He possesses super hearing, enabling him to detect distress calls from anywhere globally and respond immediately.

Anpanman's personality centers on profound selflessness and kindness. He conducts daily patrols without rest, assisting with tasks from mundane chores to perilous rescues. His defining act is sacrificing parts of his own head to feed starving individuals or animals, despite the resulting severe debilitation. This stems from an early experience where helping others and receiving gratitude brought him joy, solidifying his commitment to spreading smiles. He maintains a friendly demeanor even toward adversaries like Baikinman, attempting to correct their behavior through dialogue rather than aggression and occasionally collaborating with them against greater threats. He dislikes theatrical performances, finding them challenging. His relationships include familial bonds with Uncle Jam and Batako, mentorship of younger characters like Melonpanna and Creampanda, and alliances with fellow heroes Currypanman and Shokupanman. He rescued his loyal pet dog, Cheese, during his first patrol by offering part of his head when Cheese was starving. He treats Rollpanna with patience despite her conflicting dual hearts (one good, one evil) and views Baikinman not with hatred but as a fixture requiring redirection.

The character embodies themes of sacrifice and resilience influenced by creator Takashi Yanase's wartime experiences with starvation. Anpanman's acts of feeding others directly confront hunger-induced desperation, while his repeated regeneration symbolizes perseverance through adversity. His stories avoid lethal violence; conflicts resolve through correction rather than annihilation, emphasizing empathy and community support. These elements, alongside the existential questioning in his theme song ("Why was I born? What should I do with my life?"), frame his heroism as a continuous, reflective pursuit of purpose through service. In extended media, like the film "Chapon's Hero!", he mentors characters such as Chapon, reinforcing his role as an inspirational figure teaching the value of helping others despite personal cost. His influence extends beyond narrative boundaries, shaping cultural perceptions of heroism in Japan.