Supporting
Oh Ye-ju as Kang Ye-seo
Dong-woo's daughter and Jaehee’s best friend.
Yoo Sun as Shin Ji-hye
Kang Dong-woo's divorced ex-wife. announcer.
Hyun Bong-sik as Kim Jang-ho
Former detective of the Gangnam West Police Station in Seoul and current president of Jeil Human Resources Total Service, a criminal investigation agency.
Choi Kwang-il as Moon Chil-sung
Former police chief and current member of the National Assembly, who called Dongwoo back to Gangnam.
Choi Seong-hyeok as Dried Squid
JHRTS employee and Jangho's subordinate.
Ryu Hye-young as Seo Ji-soo
Detective from Violent Team 1 in Gangnam Western Police Station
Jeong Jae-kwang as MD Regime
Gilho's friend and Gangnam caller.
Park Ju-won as Lee Jeong-hwa
Kim Jae-hee's friend and Gangnam call girl, who was killed by Noh Jun-seo.
Song Ji-woo as Oh Jin-young
Call girl and drug addict.
Nam Jin-bok as Gil-ho's uncle
Smuggler.
Ok Ja-yeon as Choi Su-in
Gangnam pimp.
Gong Jae-Kyung as Madam Baek
Gangnam madam, who was owner of Lucky Arcade
Kim Seung-hyun as FM
Detective from Violent Team 1 in Gangnam Western Police Station
Kim Do-hyun as Ju-yun
Seoul Metropolitan Police Agency Violent Crime Investigation Team Chief Inspector and former chief of the Gangnam West Department, who was Dong-woo's superior. A corrupt police officer who looks after Club Hyena.
Lim Hyun-sung as Team Leader in Violent Crimes Team 1
Head of Strong Team 1 in Seoul Gangnam West Police Station. A corrupt police officer who follows in Jooyun's footsteps and looks after Club Hyena.
Jeong Man-sik as Tak Joo-il
Chief Prosecutor, Seoul Central District Prosecutors' Office. The person responsible for trying to cover up the Lee Jeong-hwa incident and the sponsor of Noh Jun-seo. He later became Senior Secretary for Civil Affairs, but was eventually arrested by Min Seo-jin. He was later released by Mayor Woo Dae-sik, but was eventually killed by President Choi.
Park So-ri as Ryu Hyun-kyung
Min Seo-jin’s Chief of Investigation at the Seoul Central District Prosecutors' Office.
Jeong Gi-seop as Chief Prosecutor
Chief of the Inspection Department of the Supreme Prosecutors' Office.
Kim Tae-han as Chief Ahn
Chief Prosecutor at Seoul Central District Prosecutors' Office.
Jang Won-hyung as Investigator Jang
Investigator at Min Seo-jin’s Supreme Prosecutors' Office Anti-Corruption Department.
