Cheese in the Trap

Jang Bo-ra, Seol's supportive best friend.

Professor Kang

Hong Jin-tak, Seol's father.

Ha Jae-woo, a hard working, ill-tempered senior in Seol's class.

Kwon Eun-taek, Seol and Bo-ra's loyal friend, who is in love with Jang Bo-ra.

Kong Joo-yong, Seol's neighbour and Yoon-sub's boyfriend.

Yoo Jung, Seol's senior. He is handsome, intelligent and successful, but secretly harbors a dark side to his personality. He is sometimes cold or manipulative, and has trouble forming relationships with others because of his uncertainty that they are not using him for his money. However, he is attracted to Seol.

Hong Seol, a beautiful and hardworking college student who struggles to figure out Yoo Jung's true intentions, but sees an innocent side in him against the advice of his childhood friend Baek In-ho.

Baek In-ho, a handsome and talented pianist who is adopted into Jung's wealthy family by his father. He and his sister came from a difficult background, but he finds it easy to get along with Seol, later developing feelings for her. He and Jung were friends as children, although they later develop a bitter rivalry as he believes that Jung was responsible for instigating a fight that damaged his hand, ending his dreams of becoming a concert pianist.

Baek In-ha, In-ho's beautiful, melodramatic and materialistic older sister. She was also adopted into Jung's family as a child, and is in love with Jung, although he does not reciprocate her feelings.