Jirō Jō is a 1st-year economics student at Kansei University. He is the younger twin brother of Tarō Jō. He is a resident of room 201 at Chikuseisou. Joji has a yellow spiky hair. He is often seen wearing a necklace and a long sleeve shirt underneath a yellow shirt and shorts. He and his brother played soccer for three years in high school. The only two things he knows how to cook is pasta and a simple ochazuke. Originally intending to run for the sake of becoming popular with girls, he realize that running was something enjoyable in itself.