Joo Jin-mo (actor, born 1958)

Yang Seon-chul

Ahn Yo-seop

Lee Young-ho

Kim Deok-bae

Representative Hwang

Kim Gye-hee

Yoon Jeong-geon

Park Joong-ho

Lee Myung-deuk

Manager Ko

Bong Dal

Lee Gyu-chul (Jae-in's grandfather), the chairman of the prestigious SH group who wants his grandson to learn the morals of a life instead of being a workaholic

Tojeong Yi Ji-ham, philosophy and strategy teacher of Ok-nyeo.

Professor Kim, Choi Min-woo's doctor

Jeong Cheol

Kang Ki-young (season 2)

Lee Myeong-han

Kwon Hyun-seob, publisher and Ji-yeon's boss

Choi Seok-gi

Detective

The old Korean man in Okinawa

Ham Sung-hoon

Noh Sang-hoon

Kang Woo-shik

Gong Chil-sung

Ban Chang-ho, chief detective

Ji-ahn's father

Park Sang-chul