Kim Chang-wan

Kim Chang-gyu, owner of Just Records

Oh Ji-wang

Yoo Sung-hyuk, Tae-eun's father and a university professor who wrote a thesis on Jung-hoon's condition.

Kwon Young-kook, Gi-seok's father.

Park Boo-han

Jun-hui and Gyeong-seon's father

Vice President Do Tae-geun (61 years old)

Han Hyung-sub

Park Young-shil

Kwon Soo-Myung, Moo-Hyuk's father

Lee Won-ik

Min Yong-ki

Jang Young-mok, Min-joon's lawyer who serves as a close confidant and "father figure".

Choi Soo-chul

Chairman Jung

Choi Moon-shik

Han Gyu-pil

Jang Byung-shik

Tae-yi's dad

Director Choi

General Manager Mok Young-chul

Kim Sang-chul

Kim Bok-man (cameo)

Kim Hong-shik

Park Hyun-sup

King Injo

Hwang In-soo

Woo Yong-gil

Hong Gae-shik

Kang San, head chef at the Blue House, 50 y/o

Lee Hyung-man

Soo-in's doctor

Yu-bin's father

Moon Jae-seok, Gook's godfather ("Pastor")