He has dark-grey hair that is shaven and thin eyebrows of a similar color. He wears a light green volleyball jersey with the number 3 printed in dark green.
He appears to be timid and unsure of himself at times. He lacks confidence in his abilities and doesn't seem to be very ambitious, as seen when he gave up right as the match against Kitagawa Daiichi began.
He is one of the three first years who joined Yukigaoka's Boys' Volleyball Team during Hinata's third year of junior high. They attended the Junior High Athletics Meet and were paired against the tournament favorite, Kitagawa Daiichi, in their first match. After failing to receive the ball properly and watching Hinata get blocked repeatedly, Kawashima gave up and had even questioned Hinata on his determination to win despite it being impossible. In the end, Yukigaoka was annihilated by Kitagawa Daiichi.
Kawashima appears to be a beginner at volleyball and has poor receiving skills.
Hinata was Kawashima's captain in the volleyball club when he'd joined in his first year of junior high. Like the other first years, Kawashima was unsure of what to do and relied heavily on Hinata's guidance. However, when they were paired against a powerhouse in their first match, Kawashima lost all hope immediately and was barely affected by Hinata's motivational speeches.