18 Again

Cinematography

• 
  Cho Young Jik

Composer

• 
  Mun Seong Nam

Director

• 
  Ha Byung Hoon

Screenwriter

• 
  Kim Do Yeon
• 
  Ahn Eun Bin
• 
  Choi Yi Ryun

Main Role

• 
  Kim Ha Neul

  Jung Da Jeong

  Main Role
• 
  Yoon Sang Hyun

  Hong Dae Yeong [Adult]

  Main Role
• 
  Lee Do Hyun

  Hong Dae Yeong [Teen] / Ko U Yeong

  Main Role

Support Role

• 
  Roh Jeong Eui

  Hong Si A

  Support Role
• 
  Ryeo Un

  Hong Si U

  Support Role
• 
  Wi Ha Joon

  Ye Ji Hun

  Support Role
• 
  Kim Kang Hyun

  Ko Deok Jin

  Support Role
• 
  Lee Mi Do

  Chu Ae Rin

  Support Role
• 
  Choi Bo Min

  Seo Ji Ho

  Support Role
• 
  Hwang In Youp

  Koo Ja Seong

  Support Role
• 
  Oh So Hyun

  Jeon Bo Bae

  Support Role
• 
  Lee Eun Jae

  Um So Mi

  Support Role
• 
  Ryu Da In

  Hwang Yeong Seon

  Support Role
• 
  Bin Chan Uk

  Bang Gi Yeong

  Support Role
• 
  Kim Yoo Ri

  Ok Hae In

  Support Role
• 
  Ahn Nae Sang

  Moon Sang Hwi

  Support Role
• 
  Jang Hyuk Jin

  Heo Ung Gi

  Support Role
• 
  Kim Yoon Hye

  Kwon Yu Mi

  Support Role
• 
  Go Eun Min

  Im Ja Yeong

  Support Role
• 
  Yang Dae Hyuk

  Nam Gi Tae

  Support Role
• 
  Kim Mi Kyung

  Yeo In Ja

  Support Role
• 
  Lee Byung Joon

  Hong Ju Man

  Support Role
• 
  Lee Ki Woo

  Choi Il Gwon

  Support Role
• 
  Yoo Si Yeon

  Ko U Jin

  Support Role
• 
  Han So Eun

  Jung Da Jeong [Young]

  Support Role
• 
  Kim Joong Ki

  [Teacher]

  Support Role
• 
  Kim Yun Jeong

  [Go Go Play employee]

  Support Role
• 
  Moon Woo Bin

  [Go Go Play employee]

  Support Role

Guest Role

• 
  Choi Jae Hwan

  Jin Cheol

  Guest Role
• 
  Jun Hyun Moo

  Bae Seung Hyun

  Guest Role
• 
  Ahn Mi Na

  Choi Ji Na

  Guest Role
• 
  Park Min Young

  Jin Yeong

  Guest Role
• 
  Park Yong

  Kang Jae Seon

  Guest Role
• 
  Seo Yi Soo

  Yoo Ju

  Guest Role
• 
  Kim Hye Hwa

  Lee Bo Ra

  Guest Role
• 
  Yoon Jung Hoon

  Park Hui Seong

  Guest Role
• 
  Lee Do Ha

  Lee Sang Sik

  Guest Role
• 
  Lee Do Yeon

  [Convenience store customer] (Ep. 1)

  Guest Role
• 
  Hwang Dae Ki

  Ko Deok Jin [Young] (Ep. 1-2, 9)

  Guest Role
• 
  Lee Nam Gyeong

  Hong Si A [Young] (Ep. 1, 3, 9, 12-13)

  Guest Role
• 
  Oh Ja Hun

  Hong Si U [Young] (Ep. 1, 3, 8-9, 12)

  Guest Role
• 
  Song Hoon

  [Da Jeong's PD] (Ep. 1, 7)

  Guest Role
• 
  Jung Hae Kyun

  [Dae Yeong's boss] (Ep. 1, 8-9)

  Guest Role
• 
  Jo Sang Geon

  [Dae Yeong's client] (Ep. 1, 10, 16)

  Guest Role
• 
  Jun Eun Mi

  [Pharmacist] (Ep. 2)

  Guest Role
• 
  Moon Hak Jin

  [Audition staff] (Ep. 2)

  Guest Role
• 
  Kim Han Sang

  [Construction company employee] (Ep. 2)

  Guest Role
• 
  Jang Sung Kyu

  [Self / JBC Interviewee] (Ep. 2)

  Guest Role
• 
  Kim Sun Min

  Choi Il Gwon [Young] (Ep. 2-3, 5, 7, 9)

  Guest Role
• 
  Seo Ha Yoon

  Hong Si A [Child] (Ep. 2-4)

  Guest Role
• 
  Kim Kang Hoon

  Seo Ji Ho [Young] (Ep. 3-4)

  Guest Role
• 
  Myung Seok Geun

  [Sports news staff] (Ep. 3-4)

  Guest Role
• 
  Park Kang Sub

  [Seum Wolves catcher] (Ep. 3-4)

  Guest Role
• 
  Lee Cheon Mu

  Hong Si U [Child] (Ep. 3, 8)

  Guest Role
• 
  Park Tae Yun

  [Bully] (Ep. 4)

  Guest Role
• 
  Kang Hak Soo

  [Seum Wolves GM] (Ep. 4)

  Guest Role
• 
  Im Yong Soon

  [Judge] (Ep. 5)

  Guest Role
• 
  Jang Joon Hyun

  Coach Jung [Hangkuk University Basketball coach] (Ep. 5, 7, 9)

  Guest Role
• 
  Jang Jae Kwon

  [Alumni] (Ep. 5, 14)

  Guest Role
• 
  Kim Sung Yong

  [JBC executive] (Ep. 6)

  Guest Role
• 
  O Gyu Taek

  [Shoe repairman] (Ep. 6)

  Guest Role
• 
  Lee Ju Mi

  [Mother of hearing impaired child] (Ep. 6)

  Guest Role
• 
  Go Han Min

  Reporter Kim (Ep. 6, 8, 13)

  Guest Role
• 
  Song Yoo Hyun

  Mi A [Seo Yun's mother] (Ep. 6-8, 15)

  Guest Role
• 
  Yoon Byul Ha

  Ye Seo Yun [Ji Hun's niece] (Ep. 6, 10, 15-16)

  Guest Role
• 
  Hong Ye Ji

  [Shoe saleswoman] (Ep. 6, 14)

  Guest Role
• 
  Yoo Joon Hoo

  Ye Ji Hun [Child] (Ep. 7)

  Guest Role
• 
  Jo Ryeon

  [Dae Yeong's mother] (Ep. 7-8)

  Guest Role
• 
  Im Ji Kyu

  [Ji Hun's brother] (Ep. 7, 15)

  Guest Role
• 
  Heo Jung Min

  Professor Kang [Ae Rin's ex-boyfriend] (Ep. 8)

  Guest Role
• 
  Lee Yoon Sang

  [2014 tryout interviewer] (Ep. 8)

  Guest Role
• 
  Hur Jae

  [Coach at 2009 KBU draft] (Ep. 8)

  Guest Role
• 
  Lee Soo

  Koo Ja Seong [Child] (Ep. 9)

  Guest Role
• 
  Lee Eol

  [Il Gwon's father] (Ep. 9)

  Guest Role
• 
  Kim Geon Ho

  [Gi Yong's father] (Ep. 9)

  Guest Role
• 
  Park Eun Young

  [Restaurant owner] (Ep. 9)

  Guest Role
• 
  Bae Yoo Ri

  [Yu Ju's mother] (Ep. 9-10)

  Guest Role
• 
  Kim Dong Hyun

  [Self defense trainer] (Ep. 10)

  Guest Role
• 
  Do Won Kyung

  [Self] (Ep. 10-11)

  Guest Role
• 
  Moon Ji In

  ["Couples in Crisis"] (Ep. 11)

  Guest Role
• 
  Heo Jae Ho

  ["Couples in Crisis"] (Ep. 11)

  Guest Role
• 
  Lee Chae Eun

  ["Couples in Crisis"] (Ep. 11)

  Guest Role
• 
  Kim Ho Chang

  ["Couples in Crisis"] (Ep. 11)

  Guest Role
• 
  Richard Kim

  ["Couples in Crisis" panellist] (Ep. 11)

  Guest Role
• 
  Kwak Ja Hyung

  ["Couples in Crisis" panellist] (Ep. 11)

  Guest Role
• 
  Ki Eun Yoo

  Seo Ji Ho [Child] (Ep. 14)

  Guest Role
• 
  Heo Seon Haeng

  Choi Hyeon Seung (Ep. 14)

  Guest Role
• 
  Jung Sae Rom

  [Woman bumps Da Jeong] (Ep. 14)

  Guest Role
• 
  Yong Jin

  [Private investigator] (Ep. 14)

  Guest Role
• 
  Kim Hyun Chang

  [Detective] (Ep. 15)

  Guest Role
• 
  Nam Hee Soo

  [Reporter] (Ep. 16)

  Guest Role
• 
  Woo Sang Hee

  Seo Su Rin

  Guest Role
• 
  Han Ha Rang

  [Boy]

  Guest Role
• 
  Jeon Jeong Il

  [Dad]

  Guest Role
• 
  Sung Nam

  [Doctor]

  Guest Role
• 
  Hwang Sun Young

  [Lawyer]

  Guest Role
• 
  Kim Do Hyung

  [Detective]

  Guest Role
• 
  Hwang Jung Yoon

  [30's woman]

  Guest Role
• 
  Park Ji Won

  [Delivery man]

  Guest Role
• 
  Park Beam Soo

  [Basketball team member]

  Guest Role
• 
  Jeong Seo Yul

  [Seo Ji Ho's friend]

  Guest Role
• 
  Song Da Kyung

  [Interview woman]

  Guest Role
• 
  Ho Sol Hee

  [University student]

  Guest Role
• 
  Ma Hyun Ji

  [Kids' Café teacher]

  Guest Role
• 
  Noreen Joyce Guerra

  [TV Station employee]

  Guest Role
• 
  Shin Jun Chul

  [Seongjong Electronics employee]

  Guest Role
• 
  Jin Shi Won Guest Role
• 
  Yoon Tae Soo Guest Role
• 
  Jang Yoon Woo Guest Role
• 
  Lee Ji Myeong Guest Role

Unknown

• 
  Han Seung Ho Unknown
• 
  Park Boo Gun Unknown
• 
  Park So Eun Unknown
• 
  Lim Min So Unknown
• 
  Lee Sang Hoon Unknown
• 
  Kwon Tae Jin Unknown