Seishu Handa is a professional calligrapher, despite his young age. When the elderly curator of an exhibition criticizes his calligraphy for being too unoriginal ("like a textbook"), Seishu gets angry and punches him. Because of this, his father sends him off for a retreat on Goto Island, near Kyushu. There, he meets the colorful villagers, interacts with them, and begins to find his own style.
The title of the series means "energetic/cheerful one" in the local provincial Goto Islands' dialect. The first episode is also called "Barakakodon/ばらかこどん" which means "energetic/cheerful kid", which refers to Naru Kotoishi, a very hyperactive kid that comes into Handa's life.
The prequel spin-off Handa-kun is about Seishu Handa's high school days, six years prior to the events of Barakamon.