

Lee Chang-soon
Jo Myung-jo
16
MBC
South Korea
Korean
Source: Wikipedia
Seo Yeon-joo
Im Jung-ae (Yeon-joo's roommate)
Chang Min-soo
Choi Gi-tae
Song Dae-ho (Min-soo's friend)
(cameo, episodes 1 & 10)
Choi Hyun-su (Gi-tae's father)
Choi Hee-jung (Gi-tae's sister)