By Dramabeans
Lee Na-jeong, (season 1), Kim Jin-woo (season 2), Park Yoo-young (season 2)
Lee Ah-yeon (season 1), Seo Bo-ra (season 1), Kim Sae-bom (season 1), Cha Yeon-soo (season 2), Kim Seo-hee (season 2), Kwon Ji-young (season 2)
14
2
42–56 minutes
Netflix
South Korea
Korean
Source: Wikipedia
Lee Yuk-jo, Sun-oh's new girlfriend.
Jeong Mi-mi, a popular actress who has a distant relationship with her son Sun-oh.
Kim Jo-jo, a beautiful and hardworking high school student who is bright and cheerful despite her family's painful history.
Sung Ji-yeon
Lee Wei-ju, Jo-jo's best friend
Hwang Sun-oh, a handsome model and high school student who grew up as an only child in a rich, but uncaring family with lots of problems. He falls in love with Kim Jo-jo.
Brian Cheon, developer of Love Alarm (Season 2)
Bullied student
Student
Bae Kyung-hee, Hye-yeong's loving and caring mother.
Jojo's aunt and Gul-mi's mother.
Kim Min-jae
Jang Il-sik, a vibrant judo student and Jo-jo's ex-boyfriend.
Kim Jang-go, Jo-jo's best friend. She secretly likes Il-sik. She and Jo-jo eventually drift apart.
Marx, a popular idol star.
Lee Hye-yeong, a hardworking high school student who likes Jo-jo and is the childhood friend of Sun-oh. He is the only child of a domestic helper working at Sun-oh's house.
Park Gul-mi, Jo-jo's selfish, egotistic cousin. She is a popular girl at school who likes Sun-oh but is asked out by Cheon Duk-gu, developing hatred for him. She also became jealous of Jo-jo at one point. She gradually matures and becomes more empathetic in the latter half of Season 2.