People around Kang Mi-rae

• Woo Hyun as Kang Tae-sik^[22]

Kang Mi-rae's father and a taxi driver. He is initially against Mi-rae's surgery, but later learns to accept all forms of her.

• Kim Sun-hwa as Na Eun-sim^[22]

Kang Mi-rae's mother and an insurance planner. She assists Mi-rae in receiving cosmetic surgery without the knowledge of her father.

• Min Do-hee as Oh Hyun-jung^[23]

A childhood friend of Kang Mi-rae. A first-year psychology student in Korea University who dreams of being a hip-hop musician. She has a crush on Yeon Woo-young.

People around Do Kyung-seok

• Park Joo-mi as Na Hye-sung^[22]

Do Kyung-seok's mother and CEO of a cosmetics company. Due to a divorce that resulted from an abusive marriage, she has been separated from her children for years, until she met her son again through Kang Mi-rae.

• Park Sung-geun as Do Sang-won^[22]

Do Kyung-seok's father as well as a congressman running for mayor. A self-centered and career-oriented man.

• Kim Ji-min as Do Kyung-hee^[24]

Do Kyung-seok's 17-year-old sister and an internet broadcasting jockey.

• Lee Tae-sun as Woo-jin^[25]

Do Kyung-seok's childhood friend and a bar owner.

Chemistry students

• Park Yoo-na as Yoo Eun^[26]

The freshmen (Class of 2018) representative. Her chic personality makes her popular among the students. She has an innate sense of fairness and takes no sides in any conflict. She encounters Soo-ah in her neighborhood and starts questioning her actual family background.

• Jung Seung-hye as Choi Jung-boon

A freshman. A cheerful girl from Busan with a strong accent. She has a crush on Woo-jin.

• Jung Hye-rin as Lee Ji-hyo^[27]

A freshman who is close friends with Soo-ah. Considered as the prettiest in her class after Soo-ah and Mi-rae. She is self-conscious about her physical appearance and what people think of her.

• Kim Doh-yon as Jang Won-ho^[28]

A freshman. He has a crush on Soo-ah, and treats Kyung-seok as his biggest rival.

• Kim Eun-soo as Kim Sung-woon^[29]

A freshman and Jung Won-ho's best friend.

• Oh Hee-joon as Kim Chan-woo^[30]

A student from Class of 2013. He is in his third year of repeat studies. He is known as "Master Dog" due to his crude personality. He bullies Mi-rae after she rejected his confession, and develops a crush on Soo-ah. He later gets beat up by Kyung-seok for bullying Mi-rae while Woo-young threatens to ruin his future if he ever does it again.

• Ryu Ki-san as Goo Tae-young^[31]

A second-year student. President of the student council. He has an indecisive personality and wavers in his decision to date Tae-hee.

• Baek Soo-min as Go Ye-na

A sophomore. A student council member in charge of student affairs. She used to be the most popular girl of the Chemistry Department till Soo-ah came along. She has a crush on Kyung-seok, but later develops feelings for Jung-ho.

• Bae Da-bin as Kwon Yoon-byul^[32]

The representative of the sophomores (Class of 2017). Vice president of the student council. She is decisive and responsible, with an honest and blunt personality. Because of her boyish looks, she is popular among women. She later develops a crush on Woo-young, but is rejected.

• Lee Ye-rim as Kim Tae-hee^[33]

A sophomore. She is the secretary of the student council. She feels insecure due to her plump body. She likes Tae-young.

• Choi Sung-won as Song Jung-ho^[34]

A sophomore. He is a mood maker. He has a crush on Ye-na since the first year. He joins the army after his sophomore year.

• Seo Ji-hye as Noh Min-a^[35]

A sophomore who likes to gossip.

• Kim Il-rin as Yeo-woo^[36]

The representative of the third year students (Class of 2016). A superficial person who only cares about physical appearances.

• Ham Sung-min as Jung Dong-won^[37]

A freshman. He is a motae solo and otaku with a huge presence on the Internet community. He is deluded that Soo-ah likes him.

• Kim Min-ha as Sun-mi

A second-year student. She has a great relationship with the juniors.^{[citation needed]}