Lee Soo-kyung

as Yong-soon

Choi Deok-moon

as Father

Park Keun-rok

as PE Teacher

Kim Dong-young

as Bbak-gyu

Jang Hat-sal

as Moon-hee

Choi Chan-sook

as Che-yook's Mother

Kim Ja-young

as Moon-hee's Mother

Park Chul-min

as Chief of School Administration

Kim Min-jae

as Music Teacher

Choi Yeo-jin

as English Teacher

Kim Eung-soo

as Principal

Kim Han-na

as Athletic Club Senior

Kim Ha-yeon

as Young Yong-soon

Kim Young-jae

as Birth Mother's Old Love

Lee Na-ra

as Birth Mother

Park Ji-yeon

as Art Teacher

Jang Hye-jin

as Middle-aged Woman

Kim Keum-soon

as Supermarket Worker

Na Ae-jin

as Athletic Club Member

Han Sa-myeong

as New Gym Teacher

Woo Yeon-seo

as Ethics Teacher