Cho Seung-yeon

as Seong Hyeon-guk (5 episodes)

as Yoon Jeong-ki (12 episodes)

as Homeroom teacher (1 episode)

as Apt. 702 Resident

as Seong In-jae (12 episodes)

as Kang Il-chan (4 episodes)

as dean of academic affairs (Yu-seong Tech) (10 episodes)

as Wu Cheol-yong (12 episodes)

as Chun Soo-beom (12 episodes)

as Choi Han (2 episodes)

as Kwak Se-hwan (16 episodes)

as Kim Unbu (32 episodes)

as Kyeong Geun-jik (21 episodes)

as Jin Chul-joong (24 episodes)

as Bae PD / Bae Cheol-ho (16 episodes)

as Jo Wan-gyu (12 episodes)

as Golf club member / Airplane passenger

as Lee Byeok

as Oh Hyun-chul (16 episodes)

as Yoo Jeong-ryeol (16 episodes)

as Ju Jeon (24 episodes)

as King Sun-Jo (16 episodes)

as No Young-Seok (40 episodes)

as Police Station Section Head Chief (16 episodes)