Iwamoto-sensei is the year coordinator for the second year students of Shirokin Academy and later for the third years during the next school, year.
Iwamoto has this strange habit of needing to smell things. This odd habit was first displayed in chapter one when he sniffed his shoes, and later when he was sniffing his old rugby ball. Despite the weird habit, he tries to be cordial with the staff. And like the others, takes his job seriously as a teacher, he tries to keep the students from fighting with one another.
Prior to his career as a teacher, Iwamoto was on the rugby team of his old high school.
When Yamaguchi Kumiko and Fujiyama Shizuka began working at Shirokin Academy, he was with the principal to greet them. After the principal gave his speech to both female teachers, Iwamoto-sensei was introduced to the both of them as the homeroom teacher of class 2-1 as well as their year coordinator. He explained to both new teachers the safety precautions that they should take while on campus, and warned them of the trouble their students would cause. He even prepared them both a list of troublemakers in their classes.