Good Boy

Director

• 
  Shim Na Yeon

Producer

• 
  Kim Woo Taek

Screenwriter

• 
  Lee Dae II

Main Role

• 
  Park Bo Gum

  Yun Dong Ju

  Main Role
• 
  Kim So Hyun

  Ji Han Na

  Main Role
• 
  Oh Jung Se

  Min Ju Yeong

  Main Role
• 
  Lee Sang Yi

  Kim Jong Hyeon

  Main Role
• 
  Heo Sung Tae

  Ko Man Sik

  Main Role
• 
  Tae Won Seok

  Sin Jae Hong

  Main Role

Support Role

• 
  Lee Ho Jung

  “Drug Monster” / “Drugmon”

  Support Role
• 
  Jeong Man Sik

  O Jeong Gu [Former national boxing team coach]

  Support Role
• 
  Seo Hyun Chul

  Hwang Gyeong Cheol [Chief of police]

  Support Role
• 
  Park Cheol Min

  Kim Geum Nam [Pawn shop owner]

  Support Role
• 
  Seo Jung Yeon

  Jung Mi Ja [Noodle restaurant owner]

  Support Role
• 
  Han Kyu Won

  An Dae Yong [Team leader]

  Support Role
• 
  Seo Jae Hee

  Jin Gyeong Suk [Han Na's mother]

  Support Role
• 
  Choi Myung Bin

  Ko Jeong A [Man Sik's daughter]

  Support Role
• 
  Ko Jun

  Leo

  Support Role
• 
  Kim Eung Soo

  Cho Pan Yeol [Commisioner]

  Support Role
• 
  Lee Ji Hye

  Jung Gyeong Mi [Police officer]

  Support Role
• 
  Nam Jin Bok

  Section Chief Lee

  Support Role
• 
  Kim Seo Kyung

  Kim Seok Hyeon [Prosecutor]

  Support Role
• 
  Ahn Se Ho

  Baek Seok Chun [Northeastern syndicate boss]

  Support Role
• 
  Jung Jae Won

  Lee Gwang Se [Smuggler]

  Support Role

Guest Role

• 
  Lee Kun Goo

  [Gangster] (Ep. 1)

  Guest Role
• 
  Son Ki Chul

  [Reporter] (Ep. 1)

  Guest Role
• 
  Yoo In Soo

  Bong Da Ri / “Bagboy” [Golden Rabbit leader] (Ep. 1)

  Guest Role
• 
  Lee Jung Ha

  Lee Gyeong Il (Ep. 1-3)

  Guest Role
• 
  Kang Gil Woo

  Lee Sang Gun [Geumtokipa's head] (Ep. 1-2, 9, 11)

  Guest Role
• 
  Na Ho Sook

  [Jin Su's mother] (Ep. 1-2)

  Guest Role
• 
  Lee Soo Mi

  [Grocery store owner] (Ep. 2)

  Guest Role
• 
  Kim Eun Kyung

  [Neighborhood woman] (Ep. 2)

  Guest Role
• 
  Moon Jung Dae

  [Crime scene investigator] (Ep. 2)

  Guest Role
• 
  Choi Woo Jin

  Dr. Choi U Jin (Ep. 2, 8)

  Guest Role
• 
  Kim Chan Hyung

  Correctional officer Han (Ep. 3)

  Guest Role
• 
  Kim Jong Hyeon

  [Realtor] (Ep. 3)

  Guest Role
• 
  Im Chul Hyung

  [Police captain] (Ep. 3)

  Guest Role
• 
  Song Young Chang

  O Bong Chan [Smuggler] (Ep. 3, 11-12)

  Guest Role
• 
  Lee Ji Hoon

  [Doctor] (Ep. 5)

  Guest Role
• 
  Lee Da Eun

  [Shooter] (Ep. 5)

  Guest Role
• 
  Lee Yoon Jae

  [Chief prosecutor] (Ep. 5)

  Guest Role
• 
  Choi Woo Jung

  [Nurse] (Ep. 5)

  Guest Role
• 
  Lee Ji Hoon

  Lee Hun [Neurosurgeon] (Ep. 5, 7, 10)

  Guest Role
• 
  Sung Ji Ru

  No Deok Gyu [Mayor] (Ep. 6)

  Guest Role
• 
  Kwon Dong Ho

  Park Bong Pil [Drug manufacturer] (Ep. 6)

  Guest Role
• 
  Ha Seung Yeon

  [Police officer] (Ep. 6)

  Guest Role
• 
  Kang Hak Soo

  [Manager] (Ep. 6)

  Guest Role
• 
  Han Sang Chul

  [Awakened man] (Ep. 6)

  Guest Role
• 
  Oh Jung Tae

  Dae Po Dong (Ep. 7)

  Guest Role
• 
  Choi Young Min

  [Doctor] (Ep. 8)

  Guest Role
• 
  Yoon Jong Goo

  [Protest leader] (Ep. 8-9)

  Guest Role
• 
  Lee Gyu Sub

  [Yakuza leader] (Ep. 9)

  Guest Role
• 
  Gi Hwan

  [Fencing announcer] (Ep. 9)

  Guest Role
• 
  Park Chul Min

  [Fencing announcer] (Ep. 9)

  Guest Role
• 
  Lee Su Hyung

  [Interpreter] (Ep. 9, 11)

  Guest Role
• 
  Song Hoon

  Richard Jung (Ep. 10)

  Guest Role
• 
  Lee Seo Jin

  Yun Dong Ju [Child] (Ep. 10)

  Guest Role
• 
  Ilya Belyakov

  Sergei Kirillovich Vronsky (Ep. 10-14)

  Guest Role
• 
  Woo Soo Bin

  Detective Kang (Ep. 11)

  Guest Role
• 
  Ri Min

  [Retired detective] (Ep. 11)

  Guest Role
• 
  Oh Yong Seok

  [Hyedong Oil gangster] (Ep. 11)

  Guest Role
• 
  Kim Hee Won

  [Sports commission clerk] (Ep. 11-12)

  Guest Role
• 
  Lee Young Joo

  [Doctor] (Ep. 12)

  Guest Role
• 
  Shin Kang Kyun

  [Watch seller] (Ep. 12)

  Guest Role
• 
  Min Sang Chul

  [Crime scene investigator] (Ep. 12)

  Guest Role
• 
  Lee Jung Choon

  Lee Yong Ju (Ep. 14)

  Guest Role
• 
  Jun Sung Won

  [Truck driver] (Ep. 14)

  Guest Role
• 
  Yun Ho Rim

  [Athlete] (Ep. 14)

  Guest Role
• 
  Lee Su Jeong

  Kim Yu Na

  Guest Role
• 
  Lee Han Sol

  Lee Jin Su [Export officer]

  Guest Role
• 
  Lee Dal

  “Silver Bunny”

  Guest Role
• 
  Lee Ki Sub

  Investigator Jang

  Guest Role
• 
  Shin Moon Sung

  Section Chief Song

  Guest Role
• 
  Kim Ji Yoo

  Ji Han Na [Child]

  Guest Role
• 
  Ko Ju Ni

  “Drugmon” [Child]

  Guest Role
• 
  Ko Yu Ni

  [“Drugmon's” sister / Child]

  Guest Role
• 
  Kim Young Sung

  Ji Ho Cheol [Han Na's father]

  Guest Role
• 
  Yoon Sang Won

  Yang Cheon Bae [Gang member]

  Guest Role
• 
  Park Jeong Woo

  Ryuga [Northeastern Syndicate member]

  Guest Role
• 
  Seo Han Gyeol

  [Jeong Gu's bookkeeper]

  Guest Role
• 
  Lee Chan Jong

  [Detective]

  Guest Role
• 
  Choi Seong Hyuk

  [Detective]

  Guest Role
• 
  Lee So Geum

  [Ex-convict]

  Guest Role
• 
  Joo Jin Soo

  [Tour guide]

  Guest Role
• 
  Lee Dong Gyu

  [Anchorman]

  Guest Role
• 
  Yeom Ji Hye

  [Anchorman]

  Guest Role
• 
  Im Seung Min

  [Teen shooter]

  Guest Role
• 
  Kim So Yang

  [Police officer]

  Guest Role

Unknown

• 
  Park Ji Hoon Unknown