Once in a Summer— Full Cast

Lee Byung-hun

as Yun Suk-young

Soo Ae

as Seo Jung-in

Lee Se-eun

as Lee Su-jin

Lee Hae-eun

as Bok-ja

Choi Deok-moon

as Suk-young's Senior

Jeong Seok-yong

as Mr. Kim

Na Ki-soo

as Suk-young's Father

Oh Dal-su

as Nam Gyun-soo

Yoo Hai-jin

as PD Kim

Kim Joong-ki

as Senior

Park Nam-hee

as Branch School Principal

Park Chae-ik

as Literary Society Member

Kim Do-kyoon

as Literary Society Member

Son In-yong

as Literary Society Member

Kim Jeong-ha

as Old Woman