Undercover High School

Director

• 
  Choi Jung In

Screenwriter

• 
  Im Young Bin

Main Role

• 
  Seo Kang Jun

  Jung Hae Seong / Jung Si Hyeon

  Main Role
• 
  Jin Ki Joo

  O Su A / O Bong Ja

  Main Role
• 
  Kim Shin Rok

  Seo Myeong Ju

  Main Role

Support Role

• 
  Jeon Bae Soo

  An Seok Ho [NIS team 4 team leader]

  Support Role
• 
  Jo Bok Rae

  Ko Yeong Hun [NIS team 4 agent]

  Support Role
• 
  Yoon Ga Yi

  Park Mi Jeong [NIS team 4 agent]

  Support Role
• 
  Lee Seo Hwan

  Kim Hyeong Bae [NIS director]

  Support Role
• 
  Im Chul Hyung

  Kong Jin Sang [NIS team 1 team leader]

  Support Role
• 
  Kim Min Ju

  Lee Ye Na [Student council president]

  Support Role
• 
  Park Se Hyun

  An Yu Jeong [Seok Ho’s daughter]

  Support Role
• 
  Jang Sung Bum

  Park Tae Su [Student council member]

  Support Role
• 
  Lee Hyun So

  Han Seung Jae [Student council member]

  Support Role
• 
  Kim Sun Min

  Ji Hyeon Jun [Student council vice president]

  Support Role
• 
  Shin Jun Hang

  Lee Dong Min [Student]

  Support Role
• 
  Jeong Soo Hyun

  Im Yun Cheol [Student]

  Support Role
• 
  Kang Pil Jun

  Son Beom Sik [Student]

  Support Role
• 
  Shin Ga Eun

  Choi Su Jin [Student]

  Support Role
• 
  Kim Seung Beom

  Kim Ho Jin [Informant]

  Support Role
• 
  Park Jin U

  Park Jae Mun [Byeongmun high school president]

  Support Role
• 
  Oh Yong

  Baek Gwang Do [Superintendent]

  Support Role
• 
  Lee Min Ji

  Kim Ri An [P.E. teacher]

  Support Role
• 
  Noh Jong Hyun

  Lee Jun Ho [Math teacher]

  Support Role
• 
  Kim Young Ah

  Im Cheong Ha [Su A's mother]

  Support Role
• 
  Kim Soo Jin

  Jang Man Ok [Seok Ho's wife]

  Support Role
• 
  Yun Chae Bin

  Yun Chae Rin [Student]

  Support Role

Guest Role

• 
  Kim Eui Sung

  Seo Byeong Mun [Byeongmun high school former principal] (Ep. 1)

  Guest Role
• 
  Li Yong Qun

  [Blackmarket buyer] (Ep. 1)

  Guest Role
• 
  Kyung Ki Hyun

  [Restaurant hoodlum] (Ep. 1)

  Guest Role
• 
  Oh Eui Shik

  Jung Jae Hyun [Hae Seong's father] (Ep. 1-2, 5-7, 11-12)

  Guest Role
• 
  Shin Dam Soo

  Park Min Cheol [Assemblyman] (Ep. 1, 3-4)

  Guest Role
• 
  Kang Soo Bin

  [Bully student] (Ep. 2)

  Guest Role
• 
  Jang Se Rim

  [Bully student] (Ep. 2)

  Guest Role
• 
  Jo Jae Yun

  Koo Sang Tae [Boss] (Ep. 2-4)

  Guest Role
• 
  Shin Yeon Suk

  Choi Bok Sun [Dong Min’s grandma] (Ep. 2-3)

  Guest Role
• 
  Koo Min Hyuk

  Kim Hyeon Ho [Security guard] (Ep. 2-3, 5-6)

  Guest Role
• 
  Yu Ji Wan

  Jung Hae Seong [Child] (Ep. 2, 4-7, 9, 11-12)

  Guest Role
• 
  Lee Dong Gi

  Kang Seong U [Bully] (Ep. 3)

  Guest Role
• 
  Yong Jin

  [Detective] (Ep. 3)

  Guest Role
• 
  Baek Kil Sung

  [Seong U’s dad] (Ep. 3)

  Guest Role
• 
  Park Jung Eon

  [Student’s mom] (Ep. 3)

  Guest Role
• 
  Lee Bum Chan

  [Ye Na’s driver] (Ep. 3, 5)

  Guest Role
• 
  Su Hyun

  [Student] (Ep. 4)

  Guest Role
• 
  Ahn Nae Sang

  [Neighborhood resident] (Ep. 4)

  Guest Role
• 
  Park Seol Ha

  O Su A [Child] (Ep. 4-7)

  Guest Role
• 
  Kwon Tae Won

  Chief editor Yun (Ep. 5)

  Guest Role
• 
  Kim Sung Yong

  [CCTV room staff] (Ep. 5)

  Guest Role
• 
  Lee Hwi Seo

  [Piano student] (Ep. 6)

  Guest Role
• 
  Yoo Dam Yeon

  Ms. Do [Student’s parent] (Ep. 7-8)

  Guest Role
• 
  Joo Seok Tae

  [Seung Jae’s dad] (Ep. 7-8)

  Guest Role
• 
  Lee Seo Young

  Park Min Ji [Su A’s student] (Ep. 8, 12)

  Guest Role
• 
  Kim Dae Geun

  [Gang member] (Ep. 10)

  Guest Role
• 
  Kim Nak Gyun

  [Internal affairs officer] (Ep. 10)

  Guest Role
• 
  Chae Hoon

  [Gangster] (Ep. 1)

  Guest Role