Full cast of ONE: High School Heroes

Lee Jung-ha

Kim Eui-gyeom

8 episodes

Kim Do-wan

Kang Yoon-ki

8 episodes

Kim Sang-ho

Kim Seok-tae

8 episodes

Kim Joo-ryoung

Myeong Da-bin

8 episodes

Shin Jun-seop

Nam Seung-Sik

8 episodes

Lee Chan-hyeong

Sung-Wook

8 episodes

Shin Jae-whi

Lee Ki-Yoon

8 episodes

Lim Sung-kyun

Kim Seung-joon

8 episodes

Yuk Jun-seo

Lee Geol-jae

8 episodes

Yoo Hee-je

Choi Ki-soo

8 episodes

Lim Hyun-tae

Choi Hong-il

8 episodes

Hong Min-gi

Kim Nam-hyeop

8 episodes

Shin Hyun-soo

Kim Su Gyeom [Eui Gyeom's brother]

8 episodes

Ha Mheen

Kim Ui-gyeom Aunt (Eps 3)

1 episode