Oh Jung-se

Jang Jun-sang

Eo Heung

Lee Min-woo

An Ji-hyeong

Yeom Hae-sang Ham Sung-min as young Yeom Hae-sang

Director Shin / Shin Hyun-min (Ep. 1–3, 6)

Wang Jun-hyeok, an out-of-work musician who stands on the brink of betrayal and fraud.

Do Jae-gang, Jae-jin's brother

Jung Goo-young

Dr. Lim, a researcher of vaccines.

Oh Jong-tae (Season 1)

Moon Sang-tae Lee Kyu-sung as young Moon Sang-tae

Kwon Kyeong-min

Yeon Joon-kyu, the CEO of Always Law Firm. An ardent fan of Yoon-seo.

No Gyu-tae

Kim Young-dae

Jung Ki-joon

Han Chul-ho

Kang Hyun-joon – Director of Hyunsung Hospital Foundation. He comes from a rich family and is ambitious.

Yong Goo-hyung

Prosecutor (ep. 7 & 9)

Oh Do-si

Park Sang-tae

Husband of Chungsol's CEO (cameo, ep. 20)

Goo Kwang-soo

Kim Heung-sam, planning director of ViVi cosmetics

Noh Joo-hyun

Joo Jung-myung

Goo-jak

Jae-hoon/Jay

Kwang-tae, Nan-sook's brother

Seo Jung-joon (private loan collector)