Jun Kudō is student number 9 in class 2-F. He has spiky black hair, grey eyes, and a calm expression. His personality is serious and calm, marked by a strong passion for storytelling. He consistently maintains a serious tone, even when his narratives carry a mocking intent, and generally avoids telling jokes or attempting humor.

Renowned as a "Genius Storyteller," he can tell any story. His tales often move listeners to tears, regardless of any underlying mockery. Kino views him as a rival, though Jun displays apparent indifference to this dynamic.

He lives with his grandfather and is an avid reader; he has reportedly checked out every book in the school library that Nozomu Itoshiki wishes to read. His name originates from the bookstore Junkudo-Shoten and its founder, Jun Kudō.

Within class interactions, Jun is one of the male students attracted to Nozomu Itoshiki, placing him among those with romantic interest in the teacher. By the conclusion of the manga's overarching narrative, Nozomu decides to marry all his students, including Jun alongside female students like Meru, integrating him into the resolution of the character relationships.

Throughout the series and its adaptations, including "Zan Sayonara Zetsubō Sensei Bangai-chi" and other OVAs, his established role, background, storytelling focus, and quiet demeanor remain consistent without significant alterations or unique developments specific to him.