Choi Moo-sung

Yang-cheon: a gangster.

Song Woo-byeok: CEO of Woobyeok Group and the main antagonist of the series. He is responsible for Kang-ho's father death.

Choo Young-woo: the Right Chamchan who was responsible for the murders of Kang Han-soo's parents.

Mr. Na

Seok Mun-go, an anesthesiologist and Seok Mi-jung's father.

Song Doo-cheol

Mak-chi

Jeon Bongjun, the owner of a local apothecary who becomes the revolutionary leader.

An egg seller (Ep. 5)

Jang Seung-gu Sung Yoo-bin as young Jang Seung-gu

Woo Tae-ha (season 2)

Kim Min-chul (a.k.a. "Long-term Prisoner")

King Seongjong

Yoon Seung-ro

Jang Jung-shik (Jang Kook-young's father)

A widower, he is the owner of a watch and jewellry store called Bonghwangdang, at the entrance to the alley. Moo-sung moved to Ssangmundong after the death of his wife. He was adopted into the neighborhood family as he raised Taek by himself. Quiet and reserved, Moo-sung's unassuming exterior conceals hidden depths of emotion and compassion for his son, his friends, and the neighbourhood as a whole.

Butler Ahn Byung-yeol

Lee Soo-in's father (Ep. 1)

Park Bul-hwa; Goryeo-born who become the Yuan eunuch.

Moon Deok-bae ("Safari")

Ham-gwi