"Dame Oyaji" centers on the life of a middle-aged man, Shigeo Tokuda, who struggles with the mundane realities of adulthood and the societal expectations placed upon him. Once a promising young man with dreams of success, Shigeo now finds himself stuck in a dead-end job, burdened by financial struggles, and grappling with a sense of failure. His daily life is marked by a series of comedic yet poignant misadventures as he navigates the challenges of being a "dame oyaji" (useless old man), a term that reflects his perceived inadequacy in fulfilling the traditional roles of a provider and family man.

The narrative explores Shigeo's interactions with his family, particularly his wife, who often bears the brunt of his shortcomings, and his children, who view him with a mix of pity and exasperation. Despite his flaws, Shigeo occasionally demonstrates moments of genuine effort and vulnerability, revealing a deeper layer of humanity beneath his bumbling exterior. His attempts to redeem himself, whether through small acts of kindness or misguided schemes to improve his circumstances, often lead to humorous and relatable outcomes.

The series also delves into Shigeo's relationships with his coworkers and friends, who are similarly flawed and struggling with their own insecurities. These interactions highlight the universal themes of aging, self-worth, and the pursuit of happiness in a world that often feels indifferent to individual struggles. Through its episodic structure, "Dame Oyaji" balances humor with moments of introspection, offering a candid portrayal of the complexities of adult life and the resilience required to face its challenges. The characters, while exaggerated for comedic effect, remain grounded in their humanity, making the series both entertaining and thought-provoking.