Manufactured at the Matsushiba Robot Factory on September 3, 2112, Doraemon is a robot cat from the 22nd century designated model MS-903. A production accident involving an electrical bolt left him with subpar capabilities. Originally yellow, he developed an intense phobia of mice after robotic mice chewed off his ears. A failed surgery rendered him bald, and profound sadness caused his yellow paint to wash away, revealing his permanent blue color. These experiences solidified core traits: extreme fear of medical check-ups and drastic, sometimes explosive, reactions to rodents.

Sewashi Nobi, Nobita Nobi's descendant living in poverty, acquired Doraemon due to his affordability as a substandard model. The two formed a close bond. Sewashi later sent Doraemon back to the 20th century on a mission to improve Nobita Nobi's life and prevent the family's future hardship, defining Doraemon's purpose.

Physically, Doraemon appears as an earless blue robotic cat, though characters frequently mistake him for a raccoon dog, much to his irritation. His design features a red tail acting as an emergency power switch, a collar with a bell, and palm suction cups for object manipulation. His most notable feature is a four-dimensional pocket on his abdomen, storing over 1,900 futuristic gadgets from a 22nd-century department store, like the instantaneous "Anywhere Door" or flight-enabling "Take-Copter." Retrieving the correct gadget during crises often proves difficult, leading to frantic searches and accidental production of irrelevant items.

Doraemon's personality blends compassion, anxiety, and occasional stubbornness. He exhibits deep loyalty and protectiveness towards Nobita, frequently using gadgets to solve Nobita's problems, though misuse can worsen situations. His fondness for dorayaki often sways his decisions. Interactions with cats trigger infatuation or peacemaking efforts, sometimes distracting him from duties. Despite being a robot, he experiences human-like emotions: frustration when criticized, panic under pressure, and genuine affection for friends.

Relationships are central. With Nobita, he shares a profound, interdependent bond as both guardian and companion. While frequently exasperated by Nobita's laziness and failures, Doraemon consistently supports him, recognizing Nobita's underlying kindness. He maintains a caring, sometimes competitive, dynamic with his sister robot Dorami, who occasionally ensures he undergoes check-ups. His connections extend to Nobita's friends: respecting Shizuka Minamoto's compassion, enduring Takeshi "Gian" Goda's bullying, and tolerating Suneo Honekawa's bragging, often mediating group conflicts.

The episode "Summer Vacation In The 22nd Century" demonstrates Doraemon's dedication. Returning to the future to assist Sewashi with a robot project, his eagerness causes gadget misfires: the "Machine Grower" excessively ages robots and the "Time Stupidity Bomb" disrupts a competition. Sewashi's gentle insistence that Doraemon "rest" highlights the character's unease with idleness and deep-seated need to be useful, stemming from his origins. This reinforces his core traits: technological resourcefulness paired with comedic fallibility and an emotional drive to nurture those he cares for.

Across media, Doraemon succeeds in altering the Nobi family's future. Through continuous support and adventures involving time travel and gadget-based solutions, he ensures Nobita develops resilience, marries Shizuka, and achieves a stable life, fulfilling Sewashi's mission.