Happiness Does Not Come in Grades

Lee Mi-yeon

as

Lee Eun-joo

Kim Bo-sung

as

Kim Bong-koo

Kim Min-jong

as

Son Chang-soo

Lee Duck-hwa

as

Park Gil-ho

Choi Joo-bong

as

Homeroom Teach...

Kim Il-woo

as

Mr. Jung

Yang Taek-jo

as

Lee Jung-suk

Choi Soo-hoon

as

Ahn Chun-jae

Choi Soo-ji

as

Ms. Kang

Jun Woon

as

Principal

Jeong Hye-seon

as

Eun-joo's moth...

Lee Hae-ryong

as

Eun-joo's fath...

Hwang Byung-ho...

as

Kang Moon-do

Kim Ui-sang

as

Na Chok-sae

Lee Mi-nam

as

Lee So-young