Jijii serves as the homeroom teacher for class 1-D and is known for his unusual and spirited nature, which defies expectations for someone of his advanced age. His students find him strange, a sentiment that Jijii reciprocates regarding his class. The name Jijii is a Japanese term used to address a grandfather or an elderly man. Physically, he is depicted as a male senior with gray hair and exhibits characteristics such as baldness, a beard, and a mustache.

One of Jijii's most distinctive traits is the armband he always wears on his left arm. The text displayed on this armband changes every time it is shown, often featuring episode titles or adages. He is surprisingly lively for his age and employs various scare tactics in an attempt to maintain order within his classroom. One notable example of this is his promise to stand by the beds of any students who decide to skip class.

In the context of the story, Jijii is the leader of class 1-D and has direct relationships with its students, acting as their teacher. His key relationships are primarily with the members of his class, including but not limited to Behoimi, Tsurugi Inugami, Akira Miyata, Misao Nanjou, and Akane Serizawa. No information is available regarding his background, development throughout the series, or any other notable abilities beyond his described personality and unique armband.