"Smart-san" centers on the life of a high school student named Smart, who possesses an extraordinary intellect but struggles with social interactions and everyday tasks. Despite his genius-level problem-solving abilities and academic prowess, Smart often finds himself in comedic and awkward situations due to his lack of common sense and emotional awareness. His classmates and teachers frequently misinterpret his actions, leading to misunderstandings that drive much of the series' humor.

The narrative unfolds in a school setting, where Smart's unconventional approach to life contrasts sharply with the expectations of those around him. His best friend, a more socially adept and grounded individual, often acts as a mediator, helping Smart navigate the complexities of human relationships. The dynamic between Smart and his friend serves as a core element of the story, highlighting themes of friendship, personal growth, and the balance between intellect and emotional intelligence.

Throughout the series, Smart encounters various challenges, both academic and personal, that test his abilities and force him to confront his limitations. These challenges range from solving intricate puzzles and participating in school competitions to dealing with everyday scenarios like group projects and social events. Each episode typically presents a self-contained story, often with a humorous twist, while contributing to the overarching development of Smart's character.

The supporting cast includes a diverse group of classmates and teachers, each with distinct personalities that play off Smart's quirks. These characters provide additional layers to the narrative, offering different perspectives on Smart's behavior and creating opportunities for both comedic and heartfelt moments. The series balances lighthearted comedy with occasional moments of introspection, exploring the idea that intelligence alone does not guarantee success or happiness.

"Smart-san" is structured as a slice-of-life comedy, with episodic storytelling that emphasizes character interactions and situational humor. The plot avoids heavy drama or complex story arcs, instead focusing on the everyday experiences of its protagonist and the humorous consequences of his unique worldview. This approach makes the series accessible and engaging, appealing to audiences who enjoy character-driven narratives with a comedic edge.