He has dark hair that flows downwards and several strands which stick upwards. He wears a light green volleyball jersey with the number 4 printed on the shirt and black knee-pads.
Like the other first years, Mori appears to be timid and unsure of himself.
He was one of the three first years who joined Yukigaoka Boys' Volleyball Team during Hinata's third year of junior high. They attended the Junior High Athletics Meet, but was paired against the tournament favorite, Kitagawa Daiichi, in their first match. Yukigaoka was completely annihilated by Kitagawa Daiichi.
Though he is noted to have played volleyball for a while in grade school, he appears to be a beginner and has poor receiving skills.
Hinata was Mori's captain on the volleyball team during the latter's first year of junior high. Like the other first years, Mori relied on Hinata for guidance. When Mori lost hope during the match against Yukigaoka, Hinata remained optimistic and tried to cheer him up.