It's Okay to Not Be Okay

Cinematography

• 
  Kim Dong Young

Composer

• 
  Nam Hye Seung
• 
  Park Sang Hee

Costume Designer

• 
  Cho Sang Kyung

Director

• 
  Park Shin Woo
• 
  Jung Dong Yoon

Martial Arts Director

• 
  Yang Gil Yeong

Producer

• 
  Kim Yoon Jin

Screenwriter

• 
  Jo Yong

Main Role

• 
  Kim Soo Hyun

  Moon Gang Tae

  Main Role
• 
  Seo Yea Ji

  Ko Mun Young

  Main Role
• 
  Oh Jung Se

  Moon Sang Tae

  Main Role

Support Role

• 
  Park Gyu Young

  Nam Ju Ri [Gang Tae's co-worker]

  Support Role
• 
  Jang Young Nam

  Park Haeng Ja [OK Psychiatric Hospital's head nurse]

  Support Role
• 
  Kim Chang Wan

  Oh Ji Wang [OK Psychiatric Hospital's director]

  Support Role
• 
  Kang Gi Doong

  Jo Jae Soo [Gang Tae's friend]

  Support Role
• 
  Kim Joo Heon

  Lee Sang In [Sangsangyisang Publishing Company's CEO]

  Support Role
• 
  Kim Mi Kyung

  Kang Sun Deok [Ju Ri's mother]

  Support Role
• 
  Park Jin Joo

  Yoo Seung Jae

  Support Role
• 
  Lee Eol

  Go Dae Hwan [Moon Young's father]

  Support Role
• 
  Jang Gyu Ri

  Seon Byul [OK Psychiatric Hospital nurse]

  Support Role
• 
  Kim Ki Cheon

  Kan Pil Ong [Patient]

  Support Role
• 
  Jung Jae Kwang

  Joo Jung Tae [Patient]

  Support Role
• 
  Ji Hye Won

  Lee Ah Reum [Patient]

  Support Role
• 
  Choi Woo Sung

  Oh Cha Yong [OK Psychiatric Hospital caregiver]

  Support Role
• 
  Seo Joon

  Kwon Min Seok [OK Psychiatric Hospital psychiatrist]

  Support Role
• 
  Ha Kyung Min

  [OK Psychiatric Hospital's psychiatrist]

  Support Role
• 
  Kang Ji Eun

  Park Ok Ran [Patient]

  Support Role
• 
  Joo In Young

  Yoo Sun Hae [Patient]

  Support Role
• 
  Kim Su In

  Go Moon Young [Young]

  Support Role
• 
  Moon Woo Jin

  Moon Gang Tae [Young]

  Support Role
• 
  Lee Kyu Sung

  Moon Sang Tae [Young]

  Support Role
• 
  Choi Hee Jin

  [Gang Tae and Sang Tae's mom]

  Support Role
• 
  Jung Ji Hyun

  [Publishing House staff]

  Support Role
• 
  Cheon So Ra

  [Publishing House staff]

  Support Role
• 
  Go Han Min

  [Publishing House staff]

  Support Role
• 
  Yu Yeon Seok

  [Publishing House staff]

  Support Role
• 
  Ryu Yeon Seok

  [Publishing house staff]

  Support Role

Guest Role

• 
  Bae Bo Ram

  Myoung Ji Suk [Patient] (Ep. 1)

  Guest Role
• 
  Son Kang Gook

  Kim Seung Cheol [Patient] (Ep. 1)

  Guest Role
• 
  Jo Si Yeon

  Lee Seul Bi [Moon Young's fan] (Ep. 1)

  Guest Role
• 
  Kwon Ye Eun

  Go Eun [Seung Cheol's daughter] (Ep. 1)

  Guest Role
• 
  Kim Jin

  [Nurse] (Ep. 1)

  Guest Role
• 
  Lee Sun Young

  [Nurse] (Ep. 1)

  Guest Role
• 
  Kim Tae Hoon

  [Doctor] (Ep. 1)

  Guest Role
• 
  Kim Woo Kyum

  [Caregiver] (Ep. 1)

  Guest Role
• 
  Kim Sang Il

  [Admin manager] (Ep. 1)

  Guest Role
• 
  Yu Seung Il

  [Angry professor] (Ep. 1)

  Guest Role
• 
  Park Min Young

  [Lee Seul Bi's mother] (Ep. 1)

  Guest Role
• 
  Jung Seung Kil

  [Book critic] (Ep. 2)

  Guest Role
• 
  Park Chul Min

  [TV reporter] (Ep. 2)

  Guest Role
• 
  Jo Yi Hyun

  [Dinosaur boy] (Ep. 2)

  Guest Role
• 
  Kim Geon Ho

  [Book signing parent] (Ep. 2)

  Guest Role
• 
  Lee Ji Hae

  [Book signing parent] (Ep. 2)

  Guest Role
• 
  Han Ki Joong

  Kwon Man Su (Ep. 3-4)

  Guest Role
• 
  Kwak Dong Yeon

  Kwon Gi Do [Man Su's son] (Ep. 3-4, 16)

  Guest Role
• 
  Lee Young Sook

  [Man Su's wife] (Ep. 3-4)

  Guest Role
• 
  Kang Dong Yup

  [Man Su's assistant] (Ep. 3-4)

  Guest Role
• 
  Bae Yoo Ri

  [Man Su's daughter] (Ep. 3-4)

  Guest Role
• 
  Bae Hae Seon

  Kang Eun Ja [Patient] (Ep. 4-7, 16)

  Guest Role
• 
  Park Seo Kyung

  Nam Ju Ri [Young] (Ep. 5, 9)

  Guest Role
• 
  Jung Sang Hoon

  [Motel clerk] (Ep. 5)

  Guest Role
• 
  Kwon Ha Young

  [Eun Ja's daughter] (Ep. 7-8)

  Guest Role
• 
  Choi Daniel

  Choi Daniel [Moon Young's fan] (Ep. 8)

  Guest Role
• 
  Kwon Dong Ho

  [Ah Reum's ex-husband] (Ep. 8)

  Guest Role
• 
  Lee Hwa Young

  [Ah Reum's mother] (Ep. 9)

  Guest Role
• 
  Jun Joon Woo

  [Ah Reum's brother] (Ep. 9)

  Guest Role
• 
  Choi Se in

  [Kindergarten girl] (Ep. 11)

  Guest Role
• 
  Kim Yun Seul

  [Kindergarden girl] (Ep. 11)

  Guest Role
• 
  Woo Jeong Won

  Do Hee Jae [Moon Young's mother] (Ep. 12-14)

  Guest Role
• 
  Min Kyung Jin

  [Sun Hae's father] (Ep. 13)

  Guest Role
• 
  Bae Seong Il

  [Detective] (Ep. 15)

  Guest Role
• 
  Kim Jong Ho

  Im Ui Won

  Guest Role
• 
  Go Do Yeon

  Yoo Sun Hae [Young]

  Guest Role
• 
  Park So Young

  [Nurse]

  Guest Role
• 
  Jung Ji Hwan

  [Publishing co. staff]

  Guest Role
• 
  Kim Dong Hyun Guest Role
• 
  Kim Seong In Guest Role

Unknown

• 
  Kim Young Hee Unknown
• 
  Park Tae Yun Unknown