Nobisuke Nobi, addressed as Papa within the Nobi household, is the father of Nobita, the husband of Tamako, and the adoptive father of Doraemon. He works as an ordinary salaryman in Tokyo and represents a typical middle-class Japanese father figure. His exact age is not consistently defined across the series, though some episodes place him in his mid-thirties. In his youth he closely resembled his son Nobita, and his childhood was shaped by the harsh conditions of World War II-era Japan, when he endured difficult wartime circumstances and at one point considered drowning himself. He was raised by a very strict and intimidating father and a warm, kind mother, an upbringing that influenced his later approach to parenting.

Nobisuke is gentle, easygoing, patient, and mild-mannered. He shares many of his son's traits, including clumsiness, a laid-back attitude, and a kind heart. He is far less strict than his wife Tamako, and when he does scold Nobita, he tends to reason with him calmly rather than shout out of emotion. He generally trusts Nobita and prefers to watch over him with warmth and understanding. At the same time, he has clear flaws: he is forgetful and frequently loses things, he is indecisive, he has a weak will, and he struggles with habits such as smoking, despite having attempted to quit many times. He also enjoys drinking alcohol, sometimes to excess at social gatherings, and has a habit of fidgeting. He occasionally acts selfishly at home, such as taking over the television or canceling family plans because of his own fatigue, but these moments are balanced by his underlying devotion to his family.

His greatest personal motivation comes from a long-held dream of becoming a painter. As a schoolchild he won a national prize in a drawing contest, and during middle school he studied under a painter who later became famous. When he was a young man, a wealthy family offered to sponsor his artistic studies abroad and to arrange a marriage with their daughter, but he refused because he believed that a person should carve out his own path in life rather than rely on another's wealth. He ultimately gave up his artistic ambition, became an office worker, and found his own way in life, which led him to meet and marry Tamako. He still paints from time to time, though less often than in his youth. His core motivations center on supporting his family through steady work and on teaching Nobita to become a self-reliant person who does not depend on others.

In the story, Nobisuke serves as a stabilizing presence in the Nobi household. He balances Tamako's stricter, more reactive parenting with calm guidance, and he is often the family member who mediates conflict or offers perspective. His ordinary work life, his struggles with his上司 and colleagues, and his daily routines give the family scenes a sense of everyday realism. His occasional words of advice carry particular weight because he speaks quietly and sincerely, and his willingness to listen makes Nobita more receptive to him than to his mother. Though he is rarely the center of dramatic events, his steady presence grounds the family and reinforces themes of parental love, sacrifice, and the value of ordinary hard work.

His key relationships define much of his role. With Nobita, he is patient, encouraging, and generally believing in his son's inherent goodness, though he can become firm when he sees Nobita avoiding responsibility or relying too heavily on others. On the subject of independence, he has insisted that Nobita cannot become a capable adult if he always depends on outside help. With Tamako, he has a warm and loving marriage, although she frequently takes charge of household matters and he often gives in to her. They met when he collided with her on the street shortly after refusing the offer of patronage, and he later returned the commuter pass she had dropped, which began their relationship. With Doraemon, he is fully accepting and treats the robot cat as a genuine member of the family, considering the household to be a four-person family and even keeping a family photograph that includes Doraemon at his workplace.

The character shows development mainly through flashback episodes that reveal his past. These stories show how a strict father and a loving mother shaped him, how he endured hardship during the war, and how he gradually made peace with giving up his dream of becoming a painter. His parenting is sometimes tested, and in one episode he briefly adopts an extremely severe attitude toward Nobita before returning to his usual gentle manner. Although he is usually mild and somewhat unreliable, he occasionally reveals hidden potential, such as sprinting desperately to the hospital when Nobita was born and driving skillfully on a practice course until an accident occurs. In depictions of the future, he is shown to have aged, including losing much of his hair by the time Nobita is an adult, but his warm and accepting nature remains consistent.

His notable abilities include genuine skill in painting, which was good enough to win awards in his childhood, and occasional flashes of physical energy in emergencies. In most practical matters he is unskilled: he is clumsy at household tasks, cannot cook well, is poor at sports, repeatedly fails his driver's license test, and is not good at fishing or golf even though he enjoys them. He is also known as a rain man, frequently bringing bad weather during his outings. These abilities and limitations together present him as an ordinary, imperfect father whose greatest strengths lie not in talent or accomplishment but in his patience, his kindness, and his quiet dedication to his family.