One Day

Kim Nam-gil

Kang-soo

Chun Woo-hee

Mi-so

Jung Sun-kyung

Mi-so's Mother

Im Hwa-young

Seon-hwa

Park Hee-von

Ho-jung

Yoon Je-moon

Choi Doo-yong

Kim Ye-joon

Choi Ji-ho

Kim Jung-hyun

Assistant Manager Cha

Lee Seung-yeon

Head Nurse (uncredited)

Lee Ru-ahn

Studio Complex Keeper

Kim Hye-ok

Seon-hwa's mother

Kang Sook

Mi-so's caregiver