Umezawa was originally the leader of Ippo's bullies at high school, but later became a fan of his after he became a pro boxer. During high school he would wear his hair in a pompadour style, a trademark of many Japanese delinquents. By the time they had graduated, Umezawa's relationship with Ippo changed from fan to friends, although he was not ready to admit this at the time.

During high school he was protrayed as mean and unwilling to admit that he viewed Ippo as a friend, but after graduation he grew out of his delinquent ways and was portrayed as friendly and a bit more comical. During high school and up through his years with Makunouchi Fishing Boat, he attended most of Ippo's matches, often wearing a handmade support headband and acting as Ippo's main cheer leader.

After he retired from Makunouchi Fishing Boat to become a manga artist, Itagaki Manabu took over his job. It is unknown whether he has attended any of Ippo's matches since he left. In some ways, Umezawa can be viewed as Morikawa Jouji's avatar character.