;Teachers •
Jang Na-ra as Jung In-jae, homeroom teacher •
Choi Daniel as Kang Se-chan, former top lecturer •
Um Hyo-sup as Uhm Dae-woong "Uhm Force", math teacher •
Park Hae-mi as Im Jung-soo, principal •
Lee Han-wi as Woo Soo-chul, vice principal • Oh Young-sil as Yoo Nan-hee, ethics teacher •
Yoon Joo-sang as Jo Bong-soo, gym teacher • Kwon Nam-hee as Kwon Nam-hee • Kim Yun-ah as Kim Yun-ah • Lee Won-suk as Kim Dae-soo ;Students •
Lee Jong-suk as Go Nam-soon •
Park Se-young as Song Ha-gyeong •
Ryu Hyo-young as Lee Kang-joo •
Kim Woo-bin as Park Heung-soo •
Gil Eun-hye as Gil Eun-hye •
Kwak Jung-wook as Oh Jung-ho • Choi Chang-yub as Kim Min-ki • Kim Young-choon as Byun Ki-duk • Kim Jong-hyun • Kim Dong-suk as Kim Dong-suk •
Jeon Soo-jin as Kye Na-ri •
Shin Hye-sun as Shin Hye-sun • Kim Chang-hwan as Han Young-woo •
Lee Ji-hoon as Lee Ji-hoon •
Lee Yi-kyung as Lee Yi-kyung •
Jung Yeon-joo as Student •
Ahn Ji-hyun as Ahn Ji-hyun •
Kim Dani ==Ratings==