Hajime serves as Bakabon's younger brother within the central family unit. The character appears in multiple adaptations, starting with the 2015 anime film "Tensai Bakavon ~Yomigaeru Flanders no Inu~" and subsequent media. Hajime-chan features in the 2016 live-action television adaptation as part of the Bakabon family, interacting alongside Bakabon, Bakabon's father, Bakabon's mother, Rerere no Oji-san, and Omawari-san. This iteration modernizes the setting to the present day while preserving a Shōwa period atmosphere, maintaining Hajime's established family role. In the 2018 television anime "Shinya! Tensai Bakabon," Hajime is voiced by Ai Nonaka and explicitly identified as Bakabon's younger brother. This version continues his presence within the familial context alongside Bakabon, their parents, Rerere no Oji-san, and Unagi-Inu. Across all portrayals, Hajime consistently functions as a supporting family member in the ensemble cast.