Hiroshi Nohara is the father of the Nohara family and works as a section chief in the sales department at the Futaba Corporation, serving as the household's sole source of income. At 35 years old, he stands about 180 centimeters tall and was born and raised in Omagari, Akita (now part of Daisen) before moving to Kasukabe, Saitama, where he lives with his family. He left college and began working at his company fifteen years ago, and carries the ongoing financial responsibility of a 32-year mortgage on the family home.

In terms of personality, Hiroshi embodies the classic Japanese salaryman, enduring long workdays, packed commuter trains, and the pressures of office life. Despite these stresses, he maintains a generally laid-back, easygoing, and sometimes mischievous demeanor at home. He is a loving and devoted husband to his wife, Misae, and a caring father to his son, Shinnosuke, and daughter, Himawari. A recurring character trait is his weakness for attractive women, and he often shares with his son a tendency to admire pretty ladies, which consistently provokes the ire of his wife. While he dreams of office romances or being a playboy while asleep, he remains fundamentally faithful to his family when awake.

Motivationally, Hiroshi is driven by a deep-seated commitment to provide for and protect his family. His role as the breadwinner is a core part of his identity, and he works overtime to meet the family's financial needs. Although he often grumbles about his small allowance or bickers with Misae over minor household issues, his actions consistently reveal that his family's well-being is his top priority. In times of crisis or when his loved ones are threatened, his easygoing nature gives way to remarkable courage, resourcefulness, and a willingness to fight for them using any means necessary.

Within the family dynamic, Hiroshi acts as a counterbalance to Misae's stricter, more authoritarian discipline. While Misae is quick to anger and often uses physical reprimands, Hiroshi prefers to reason with his children, using patient guidance or playful negotiation rather than punishment. He enjoys a playful bond with Shinnosuke, often indulging in or being dragged into his son's antics, which can sometimes frustrate his wife. With his daughter Himawari, he is notably gentle and doting. The relationship between Hiroshi and Misae is one of enduring love masked by frequent, comedic conflict, usually over finances, his wandering eye, or household chores, with Misae maintaining totalitarian control over the family budget.

Throughout the series, Hiroshi shows subtle signs of development, primarily in his growing comfort and engagement with family life. While he occasionally dreams of escape, he demonstrates an increasing, if sometimes reluctant, participation in domestic duties and childcare. He made a significant sacrifice by quitting smoking for the health of his unborn daughter, Himawari, showcasing his underlying dedication. On the rare occasions he has to be away from his family for an extended period, such as a business trip, he becomes visibly emotional at the thought of being separated from them.

Hiroshi possesses a number of notable abilities, both practical and comedic. He is skilled at driving cars and motorcycles, once traveling with Shinnosuke to his hometown on a motorcycle with a sidecar. He is also handy with do-it-yourself projects, having built a doghouse for the family pet, Shiro. In movies and more serious situations, he has demonstrated surprising fighting skills, sometimes using a form of kung-fu, and showing great bravery. However, his most famous and formidable "ability" is the overwhelmingly pungent odor of his feet and socks. This smell is so potent that it can knock out his own family members, friends, and even enemies, and it is often used by other family members as a comedic weapon.