While You Were Sleeping

Composer

• 
  Park Se Jun

Director

• 
  Oh Choong Hwan
• 
  Park Soo Jin

Screenwriter

• 
  Park Hye Ryun

Main Role

• 
  Bae Suzy

  Nam Hong Ju

  Main Role
• 
  Lee Jong Suk

  Jung Jae Chan

  Main Role
• 
  Lee Sang Yeob

  Lee Yu Beom

  Main Role
• 
  Jung Hae In

  Han Woo Tak

  Main Role

Support Role

• 
  Hwang Young Hee

  Yoon Moon Sun [Hong Ju's mother]

  Support Role
• 
  Shin Jae Ha

  Jung Seung Won

  Support Role
• 
  Kim Won Hae

  Choi Dam Dong [Investigator]

  Support Role
• 
  Park Jin Joo

  Moon Hyang Mi

  Support Role
• 
  Lee Gi Young

  Park Dae Young

  Support Role
• 
  Go Sung Hee

  Shin Hee Min [Prosecutor]

  Support Role
• 
  Bae Hae Seon

  Son Woo Joo

  Support Role
• 
  Min Sung Wook

  Lee Ji Kwang [Prosecutor]

  Support Role
• 
  Son San

  Min Jung Hee [Dae Young's secretary]

  Support Role
• 
  Lee Bong Ryun

  Go Pil Sook [Hee Min's paralegal]

  Support Role
• 
  Oh Eui Shik

  Bong Du Hyeon [Reporter]

  Support Role
• 
  Lee Yoo Joon

  Oh Kyung Han [Police officer]

  Support Role
• 
  Pyo Ye Jin

  Cha Yeo Jung [Police officer]

  Support Role
• 
  Lee Do Gyeom

  Myung Dae Gu [Seung Won's classmate]

  Support Role
• 
  Nam Da Reum

  Jung Jae Chan [Young]

  Support Role
• 
  Shin Yi Joon

  Nam Hong Joo [Young]

  Support Role
• 
  Lee Jae Kyoon

  Choi Dam Dong [Police officer]

  Support Role
• 
  Ko Woo Rim

  Jung Seung Won [Young] [Past] / Chan Ho [Woo Joo's son] [Present]

  Support Role

Guest Role

• 
  Im Ga Young

  [High school student] (Ep. 1)

  Guest Role
• 
  Shim Wan Joon

  [Man with mustache] (Ep. 1)

  Guest Role
• 
  Yeo Hoe Hyun

  Lee Yu Beom [Young] (Ep. 1-2)

  Guest Role
• 
  Jang Hyun Sung

  Jung Il Seung [Jae Chan's father] (Ep. 1, 5-6, 29)

  Guest Role
• 
  Kim Do Hye

  [Kindergartner] (Ep. 3)

  Guest Role
• 
  Choi Won Young

  Nam Chul Doo [Hong Joo's father] (Ep. 3-4)

  Guest Role
• 
  Um Hyo Sup

  Park Jun Mo [So Yoon's father] (Ep. 3-5, 7-8)

  Guest Role
• 
  Jang So Yeon

  Do Geum Sook [So Yoon's mother] (Ep. 3-8)

  Guest Role
• 
  Kim So Hyun

  Park Soo Yoon [Seung Won's friend] (Ep. 3-8, 16, 32)

  Guest Role
• 
  Hong Kyung

  Choi Uk Hyeon [Deserter] (Ep. 3, 6, 29, 31)

  Guest Role
• 
  Kim Da Ye

  Kang Cho Hee [Dae Hee's sister] (Ep. 3, 8-13, 15, 32)

  Guest Role
• 
  Lee Jung Eun

  [Jae Chan's mother] (Ep. 5-6)

  Guest Role
• 
  Park Young Soo

  [Car salesman] (Ep. 6)

  Guest Role
• 
  Jo Mi Nyeo

  [Ji Kwang's paralegal] (Ep. 6, 19, 27-28, 32)

  Guest Role
• 
  Kang Ki Young

  Kang Dae Hee [Fried chicken restaurant owner] (Ep. 9-13)

  Guest Role
• 
  Kang Shin Hyo

  Gyoo Won (Ep. 10)

  Guest Role
• 
  Shin Eun Jung

  Kim Joo Young [Chief judge] (Ep. 11-12)

  Guest Role
• 
  Moon Ah Ram

  [Yu Beom's firm's receptionist] (Ep. 11, 15-17, 27-28)

  Guest Role
• 
  Cha Jung Won

  Yoo Soo Kyung [Archer] (Ep. 13-14, 16, 20)

  Guest Role
• 
  Baek Sung Hyun

  Do Hak Young [Cable man] (Ep. 13-20)

  Guest Role
• 
  Jeon Gook Hwan

  Yoo Man Ho [Su Gyeong's father] (Ep. 15, 17-20)

  Guest Role
• 
  Lee Min Jae

  [Seung Won's classmate] (Ep. 17-19

  Guest Role
• 
  Yoo In Soo

  [Seung Won's classmate] (Ep. 17-19)

  Guest Role
• 
  Moon Xion

  Lee Hwan [Tae Min's student] (Ep. 19, 21-23)

  Guest Role
• 
  Yoon Kyun Sang

  [Lovers] (Ep. 21)

  Guest Role
• 
  Lee Sung Kyung

  [Lovey-dovey couple] (Ep. 21)

  Guest Role
• 
  Lee Ga Ryeong

  [Hospital coordinator] (Ep. 21)

  Guest Role
• 
  Ryu Tae Ho

  Moon Tae Min [Professor] (Ep. 21-24)

  Guest Role
• 
  Jung Hyun Seok

  [Chan Ho's doctor] (Ep. 21-24)

  Guest Role
• 
  Kim Gi Cheon

  [Lee Hwan's father] (Ep. 21-24, 32)

  Guest Role
• 
  Woo Sung Min

  [Kindergartner] (Ep. 22)

  Guest Role
• 
  Jo Yeon Ho

  Im Se Young [Witness] (Ep. 22-23)

  Guest Role
• 
  Lee Joo Suk

  [Presiding judge] (Ep. 23-24)

  Guest Role
• 
  Hong Hee Won

  [Doctor expert witness] (Ep. 23-24)

  Guest Role
• 
  Lee Jae Won

  Jo Yoon Pyo [Phone buyer] (Ep. 25-28)

  Guest Role
• 
  Yoon Yong Hyun

  Park Dae Young [Phone thief] (Ep. 25-26)

  Guest Role
• 
  Kim Su In

  [Thief's daughter] (Ep. 26)

  Guest Role
• 
  Lee Na Ra

  Ha Joo An [IV drip serial killer] (Ep. 28-30)

  Guest Role
• 
  Son Byung Ho

  President Go (Ep. 29-31)

  Guest Role
• 
  Im Jae Geun

  [Reporter]

  Guest Role
• 
  Park Sang Hwi

  [Yu Beom's driver]

  Guest Role
• 
  Ham Jin Sung

  [Court inspector]

  Guest Role
• 
  Min Chae Eun Guest Role

Unknown

• 
  Kim Oh Bok Unknown
• 
  Park Tae Yun Unknown
• 
  Son Jung Rim Unknown
• 
  Yoon Jae Hyun Unknown
• 
  Park Min Young Unknown