Still 17

Composer

• 
  Mun Seong Nam

Director

• 
  Jo Soo Won
• 
  Kim Young Hwan

Screenwriter

• 
  Jo Sung Hee

Main Role

• 
  Shin Hae Sun

  Woo Seo Ri

  Main Role
• 
  Yang Se Jong

  Gong Woo Jin

  Main Role
• 
  Ahn Hyo Seop

  Yoo Chan

  Main Role
• 
  Ye Ji Won

  Jennifer / Hwang Mi Jung [Mysterious housekeeper]

  Main Role

Support Role

• 
  Wang Ji Won

  Kim Tae Rin [Violinist, music director]

  Support Role
• 
  Yoon Sun Woo

  Kim Hyung Tae [Neurology resident]

  Support Role
• 
  Jung Eugene

  Kang Hee Soo [Woo Jin's boss]

  Support Role
• 
  Yoon Chan Young

  Kong U Jin [Young]

  Support Role
• 
  Park Si Eun

  Woo Seo Ri [Young]

  Support Role
• 
  Lee Ah Hyun

  Kong Hyeon Jeong [U Jin's sister]

  Support Role
• 
  Ahn Seung Gyun

  Jin Hyun [Design staff]

  Support Role
• 
  Jo Hyun Sik

  Han Duk Soo

  Support Role
• 
  Lee Do Hyun

  Dong Hae Beom [Chan's friend]

  Support Role
• 
  Lee Seung Jun

  Kim Hyun Kyu [Seo Ri's uncle]

  Support Role
• 
  Sim Yi Young

  Kook Mi Hyun [Seo Ri's aunt]

  Support Role
• 
  Kim Min Sang

  Yoo Joong Seon [Psychologist]

  Support Role
• 
  Im Byung Ki

  Gong Yong Hwan [Gong Woo Jin's father]

  Support Role
• 
  Jo Yoo Jung

  Lee Ri An [Taesan High, crush on Chan]

  Support Role
• 
  Park Jong Hoon

  Shim Myung Hwan [Conductor, renowned violinist]

  Support Role
• 
  Lee Seo Yeon

  No Su Mi [Seo Ri's best friend]

  Support Role
• 
  Ha Do Kwon

  [Rowing crew coach]

  Support Role

Guest Role

• 
  Won Mi Won

  [Woman in park] (Ep. 11, 13)

  Guest Role
• 
  Song Ji Hyun

  [Flower store employee] (Ep. 25-26)

  Guest Role
• 
  Shin Ji Yeon

  [Violin academy director]

  Guest Role
• 
  Kim Baek Ri

  [Nurse]

  Guest Role
• 
  Jin Yu Chan

  [Kid]

  Guest Role
• 
  Ju Ah Yeon

  [Part-time worker]

  Guest Role
• 
  Uhm Hye Soo Guest Role
• 
  Ahn Dong Yeob Guest Role
• 
  Sung Hyun Mi

  [Woman who calls from flyer]

  Guest Role
• 
  Heo Yeong Son

  [Intern]

  Guest Role

Bit part

• 
  Joey Albright

  [Camper] (Ep. 1)

  Bit part
• 
  Henny Savenije

  [German audition judge] (Ep. 1)

  Bit part
• 
  Lee Tae Geom

  [Hyung Tae's senior] (Ep. 1)

  Bit part
• 
  Jung Shi Yool

  (Ep. 3)

  Bit part
• 
  Lee Joon Hee

  [Design client] (Ep. 12)

  Bit part
• 
  Lee Kyung Hoon

  [Boy on street] (Ep. 22)

  Bit part
• 
  Wang Seok Hyun

  Kim Hyung Tae [Young]

  Bit part
• 
  Jeon Bae Soo

  Woo Seong Hyeon [Seo Ri's father]

  Bit part
• 
  Jun Ik Ryoung

  Kim Hyun Jin [Seo Ri’s mother]

  Bit part
• 
  Kwon Hyuk Soo

  CEO Park [Design client]

  Bit part
• 
  Jung Jin Woon

  Jung Jin Woon [Chan’s rival]

  Bit part
• 
  Son San

  [Nurse]

  Bit part
• 
  Seo Yoon Ah

  CEO Kim [Design client]

  Bit part
• 
  Park Seung Tae

  Woo Seo Ni [Woman in bar]

  Bit part
• 
  Jung Ho Bin

  Byung Gyu Chul [Festival chairman]

  Bit part
• 
  Kim Kwang Gyu

  [Violin repairman]

  Bit part
• 
  Ji Dae Han

  [Precinct station police officer]

  Bit part
• 
  Hong Ki Joon

  Kim Sang Shik [Truck driver]

  Bit part
• 
  Lee Young Eun

  [Kim Tae Jin's sister]

  Bit part
• 
  Seo Yun Hyuk

  Yoo Chan [Young]

  Bit part
• 
  Baek Jae Jin

  [Stage design chief]

  Bit part
• 
  Ri Min

  [Teacher at Taesan high school]

  Bit part
• 
  Jo Yi Hyun

  Min Kyu [Seo Ri's cousin]

  Bit part
• 
  Park Hyun Jung

  [Tae Rin's mother]

  Bit part
• 
  Jung Kyung Cheon

  [Police precinct]

  Bit part
• 
  Lee Jin Mok

  [Security guard at Columbarium]

  Bit part
• 
  Jo Soo Ji

  Kim Tae Rin [Young]

  Bit part
• 
  Park Yoon Young

  [Seo Ri's friend]

  Bit part
• 
  Kim Young Jae

  Kim Tae Jin [Jennifer's husband]

  Bit part
• 
  Seo Eun Yool

  Yoo Chan [Young]

  Bit part
• 
  Kim Joo Ah

  [Shows Seo Ri the free food line]

  Bit part
• 
  Kim Mi Hye

  [Nurse]

  Bit part
• 
  Song Chang Gyu

  [Chicken restaurant owner]

  Bit part
• 
  Ok Joo Ri

  [Cleaning lady at airport]

  Bit part
• 
  Yoo Ok Joo

  [Nursing care worker]

  Bit part
• 
  Jo Mi Nyeo

  [Customer at Jennifer's shop]

  Bit part
• 
  Lee Hyo Bi

  Woo Seo Ri [Young]

  Bit part
• 
  Lee Yoo Jin

  [Jazz festival music crew]

  Bit part
• 
  Kim Min Seo Bit part
• 
  Moon Hak Jin Bit part
• 
  Kim Do Ah Bit part

Unknown

• 
  Shin Soo Hyun Unknown
• 
  Kwon Yoo Na Unknown
• 
  Lee Myung Joon Unknown
• 
  Kim Hye Ran Unknown