Pemeran Oh! Youngsim

Song Ha Yoon

as O Yeong Sim

Pemeran Utama

Lee Dong Hae

as Wang Gyeong Tae / Mark Wang

Pemeran Utama

Lee Min Jae (이민재)

as Lee Chae Dong

Pemeran Utama

Ryu Hyo Young

as Koo Wol Suk

Pemeran Utama

Song Young Jae

as O Dae Gwang

Pemeran Pembantu

Wang Ji Hye

as O Jin Sim

Pemeran Pembantu

Tony Ahn

as Lee U Sang

Pemeran Pembantu

Ga Young

as O Sun Sim / O Ha Yun

Pemeran Pembantu

Cho Yu Ha

as Lee Ji Yu

Pemeran Pembantu

Lee Do Yeop

as Heo Gil Dong

Pemeran Pembantu

Moon Jung Gi

as Jang Hwan

Pemeran Pembantu

Lami

as Sang Eun

Pemeran Pembantu

Song Jae Ha

as Nam Gi Ho

Pemeran Pembantu

Jo Ah Jin

as Hui Jin

Pemeran Pembantu

Chae Hyung Won

as Han Yo Han [Idol] (Ep. 1)

Bintang Tamu

Kim Sae Rom

as [OSN staff] (Ep. 1)

Bintang Tamu

Sa Hye Jin

as [Flight attendant] (Ep. 1)

Bintang Tamu

Im Seung Min

as Kim Jin U (Ep. 2)

Bintang Tamu

Son Su Min

as [Kingvely employee] (Ep. 3)

Bintang Tamu

Ban Hye Young

as Yeo Mi Ho (Ep. 6)

Bintang Tamu

Heo Ga Yoon

as Jung Yeo Ul (Ep. 6-7)

Bintang Tamu

Choi Mi Hye

as [Yoga instructor] (Ep. 7)

Bintang Tamu

Park Sun Joo

as [Min Ji's friend] (Ep. 8)

Bintang Tamu

Uhm Chae Young

as Kim Min Ji (Ep. 8-9)

Bintang Tamu

Moon Woo Jin

as Kang U Chan (Ep. 8-9)

Bintang Tamu

Jo Yi Hyun

as Wang Gyeong Tae [Young]

Bintang Tamu

Lee Hyo Bi

as O Sun Sim [Young]

Bintang Tamu

Eom Seo Hyun

as O Yeong Sim [Young]

Bintang Tamu

Kim Da Eun

as Kim Jeong Jin

Bintang Tamu

Kim Si Duk

as Lee Sam Du

Bintang Tamu

Choi Seung Won

as Yoo Ho Jae

Bintang Tamu

Oh Hwan Min

Sutradara

Kim Gyeong Eun

Sutradara

Jeon Seon Young

Screenwriter