Hayama has short, messy black hair and large, teal eyes. He wears a red jumper with thin white stripes that run over the chest, then turn downwards before meeting. He wears a soft purple scarf, black trousers and brown loafers. His eyes are usually shadowed over and wide in fright. He also sweats a lot due to almost constant panic.
Hayama is horribly paranoid, be it of others, where he is, or anything else, which has caused his parents to get him to go to the support meeting to help him try and cope with, if not overcome, his near-crippling paranoia. Of course, being packed into a small space with so many unfamilliar people, one of whom has an explosive temper, does not bode well with him and he dislikes being there.
Hayama's first name is traditionally used as a last name, and the kanji of his last name comes from Tsuri Goshi (釣腰,Tsuri Goshi?), a judo throw.