Psychopath Diary

Composer

• 
  Eom Ki Yeop

Director

• 
  Lee Jong Jae

Screenwriter

• 
  Ryu Yong Jae
• 
  Kim Hwan Chae
• 
  Choi Sung Joon

Main Role

• 
  Yun Si Yun

  Yook Dong Shik

  Main Role
• 
  Jung In Sun

  Shim Bo Kyung

  Main Role
• 
  Park Sung Hoon

  Seo In U

  Main Role

Support Role

• 
  Lee Han Wi

  Yook Jong Cheol [Dong Sik's father / Restaurant owner]

  Support Role
• 
  Hwang Geum Byul

  Yook Ji Yun [Dong Shik's big sister]

  Support Role
• 
  Kim Kyul

  Jo Yong Gu [Dong Shik's brother-in-law]

  Support Role
• 
  Jung Su Bin

  Yook Dong Chan [Dong Shik's half-brother / 11th grader]

  Support Role
• 
  So Hee Jung

  Na In Hye [Dong Shik's stepmother]

  Support Role
• 
  Choi Sung Won

  Heo Taek Soo [Constable / Bo Kyung's companion]

  Support Role
• 
  Kim Myung Soo

  Shim Suk Gu [Bo Kyung's father / Former Ace Detective]

  Support Role
• 
  Lee Kan Hee

  Lee Suk Yun [Bo Gyeong's mother / Cafe owner]

  Support Role
• 
  Lee Hae Young

  Ryu Jae Joon [Criminal Profiler / Bo Kyung's uncle]

  Support Role
• 
  Park Jung Hak

  Seo Chung Hyun [In Woo's father / Chairman of Daehan Securities]

  Support Role
• 
  Yu Bee

  Seo Ji Hun [In Woo's step-brother / Managing Director of Daehan Securities]

  Support Role
• 
  Yoon Ye Hee

  Kim Eun Shil [Chung Hyun's wife / Ji Hun's mother]

  Support Role
• 
  Kim Hye Na

  Seo Ji Yun [In Woo's step-sister]

  Support Role
• 
  Hwang Sun Hee

  Jo Yu Jin [Audit Team Leader]

  Support Role
• 
  Choi Dae Chul

  Gong Chan Suk [Dong Shik's boss / Asset Management Team Leader]

  Support Role
• 
  Kim Ki Doo

  Park Jae Ho [Dong Sik's colleague / Asset Management Team deputy]

  Support Role
• 
  Jo Si Nae

  Han Jung Ah [Dong Shik's colleague]

  Support Role
• 
  Choi Tae Hwan

  Shin Suk Hyun [Dong Shik's colleague]

  Support Role
• 
  Lee Min Ji

  Oh Mi Joo [Dong Shik's colleague]

  Support Role
• 
  Heo Sung Tae

  Jang Chil Sung [Retired Gangster]

  Support Role
• 
  Han Soo Hyun

  Kim Mu Suk [In Woo's aide | former detective]

  Support Role

Guest Role

• 
  Jung Hae Kyun

  Kim Myung Guk [Homeless man] (Ep.1-2, 4)

  Guest Role
• 
  Yura

  [Woman walking dog] (Ep. 2)

  Guest Role
• 
  Han Ji Eun

  [Passerby's girlfriend] (Ep.2)

  Guest Role
• 
  Nam Jung Hee

  [Murder victim] (Ep.2, 4)

  Guest Role
• 
  Yun Ji On

  Joo Young Min [Firm Executive] (Ep.4-5)

  Guest Role
• 
  Lim Il Gyu

  Kim Chan Il [In Woo's brother-in-law]

  Guest Role
• 
  Seong Chan Ho

  [Caretaker of Memorial Park] (Ep. 9)

  Guest Role
• 
  Lee Dong Yong

  [Prisoner] (Ep.12-13)

  Guest Role
• 
  Mi Seok

  [Prisoner] (Ep.12-13)

  Guest Role
• 
  Ok Joo Ri

  [Neighbor of driver in crash] (Ep. 13)

  Guest Role
• 
  Gyeol Hwi

  [Reporter] (Ep.16)

  Guest Role
• 
  Kim Mo Bum

  Nergui [Mongolian factory worker]

  Guest Role
• 
  Shin Soo Hang

  [Doctor's friend]

  Guest Role
• 
  Lee Dong Gyu

  [News Anchor]

  Guest Role
• 
  Oh Chae Eun

  [Seo Ji Hun's Secretary]

  Guest Role
• 
  Jin Shi Won

  [Reporter] (Ep. 1, 12)

  Guest Role
• 
  Lee Jang Ho

  [Nurse] (Ep 8)

  Guest Role
• 
  Moon Chang Jun

  [Park Jae Ho's co-worker] (Ep. 16)

  Guest Role
• 
  Jeon Soo Yeon

  [Nurse] (Ep. 8-9)

  Guest Role
• 
  Lee Do Hye

  [Escape room player](Ep. 16)

  Guest Role
• 
  Yoo Sung Yeol

  [Escape room player] (Ep. 16)

  Guest Role
• 
  Jin Yu Chan

  Yook Dong Chan [Child]

  Guest Role
• 
  Kim Jang Hwan

  [Anchor]

  Guest Role
• 
  Shin Soo Oh

  [Doctor's friend]

  Guest Role
• 
  Jung Chul Soon

  [Dong Shik's colleague in bathroom]

  Guest Role
• 
  Jo Hyun Woo

  Nam Sung Cheol (Ep. 8)

  Guest Role
• 
  Song Hoon

  [asset management team leader of Daehan Stock]

  Guest Role
• 
  Park Ki Ryung Guest Role
• 
  Yang Hee Jae

  Seo Ji Hun [Child]

  Guest Role
• 
  Ha Jin

  [ER Nurse]

  Guest Role
• 
  Koo Ja Keon

  [Bully]

  Guest Role
• 
  Yong Jin Guest Role
• 
  Lee Hyun Woong Guest Role
• 
  Jang Eui Don

  [Bus driver]

  Guest Role
• 
  Kim Ah Ram

  [Nurse] (Ep. 16)

  Guest Role
• 
  Lee Su Min

  Hong Jin Gu

  Guest Role
• 
  Yoon Kyung Ho Guest Role
• 
  Jo Yoon Ho

  [Gang boss]

  Guest Role
• 
  Kim Nam Ho

  [Accommodation staff]

  Guest Role

Bit part

• 
  Seo Jin Won

  Min Suk (Ep. 4)

  Bit part
• 
  Kim Joon Kyung

  Bartender (Ep. 10)

  Bit part

Unknown

• 
  Kim Sung Gon Unknown
• 
  Im Ho Joon Unknown
• 
  Kwon Chan Min Unknown
• 
  Jo Eun Yoo Unknown
• 
  Yoon Sung Won Unknown