Ma Jin-joo (12 episodes, 2017)
Choi Ban-do (12 episodes, 2017)
Jung Nam Gil [Jin Joo's sunbae] (12 episodes, 2017)
An Jae Woo [Ban Do's friend] (12 episodes, 2017)
Yoon Bo Reum [Jin Joo's friend] (12 episodes, 2017)
Go Dok Jae [Ban Do's friend] (12 episodes, 2017)
Go Eun Sook [Jin Joo's mother] (12 episodes, 2017)
Ma Pan Seok [Jin Joo's father] (12 episodes, 2017)
Choi Ki Il [Ban Do's father] (11 episodes, 2017)
Min Seo Yeong [Ban Do's first love] (10 episodes, 2017)
Cheon Seol [Jin Joo's friend] (9 episodes, 2017)
Park Hyun-suk (7 episodes, 2017)
History department senior (1 episode, 2017)
Jin-joo's sister (unknown episodes)
Kang Kyung-sook (unknown episodes)