Main •
Hwang Jung-eum as Seo Hyun-ju •
Joo Ye-rim as Seo Hyun-ju (child) • Lee Chae-yoon as Seo Hyun-ju (teen) •
Yoon Hyun-min as Hwang Ji-woo • Jung Ji-hoon as Hwang Ji-woo (child) •
Bae In-hyuk as Hwang Ji-Woo (teen) •
Seo Ji-hoon as Park Do-gyeom • Ha Yi-ahn as Park Do-gyeom (child) •
Jo Woo-ri as Han Seo-yoon •
Choi Myung-gil as Kim Seon-hee
Supporting People around Seo Hyun-ju •
Hwang Young-hee as Jung Young-soon, Hyun-ju's mother and Park's adopted mother •
Seo Hyun-chul as Seo Ho-joon, Hyun-ju's father and Park's adopted father • Song Sang-eun as Kang Min-jung • Noh Susanna as Oh Young-eun • Kim Gyu-sun as Song Jin-ah
People around Hwang Ji-woo • Lee Hwang-eui as Nam Yoo-cheol, Hwang Ji-woo's secretary • Kang Ji-eun as Hwang Ji-woo's mother
Sunwoo Webtoon Team •
Han Da-sol as Kim Da-eun •
Jo Hyun-sik as Kang Eun-jae • Hwang Man-ik as Kim Pal-do •
Baek Joo-hee as Jo Mi-ok • Yoo Jung-rae as Hong Bo-hee
Mytoon Webtoon (Ep.1-3) •
In Gyo-jin as In Gyo-seok •
Lee Si-eon as Oh Si-eon, webtoon writer • Lee Mal-nyeon as Writer Lee • Joo Ho-min as Writer Joo
Others • Kim Da-ye as Kim Su-jeong • Lee Jung-yeol as Jung Seok-woo, Hwang Ji-woo's doctor • Lee Hyun-kyun as Kang Min-jung's husband • Shim Hye-yeon as Soo-bin Kang Min-jung's daughter • Song Jin-woo as Kim Eun-beom, Song Jin-ah's ex-husband • Kim Doh-yon as Oh Ji-hwan, Park Do-gyeom's friend and Song Jin-ah's boyfriend
Special appearances • Son Sung-chan as Bae Jae-joon (Ep. 1) • Ahn Se-bin as Oh Young-eun (child) (Ep. 1) •
Kang Dong-ho as Man at wedding (Ep. 1) • Seo Yoon-hyuk as Seo Hyun-ju's classmate (Ep. 1) •
Johyun as Yu-na (Ep. 1) •
Yoon Sun-woo as Seo Hyun-ju's ex-boyfriend (Ep. 1, 2) •
Lee Jong-hyuk as Seo Hyun-ju's blind date (Ep. 3) •
Kim Jae-hwa as Butler Kim (Ep. 6) •
Lee Seon-hee as Italian Table owner (Ep. 4) •
Shin Se-hwi as You Gyo Girl, webtoon writer (Ep. 8, 10-11) • Woo Hyun-joo as You Gyo Girl's mother (Ep. 8, 10-11) • Jwa Chae-won as fellow student (Ep. 11,14) • Won Jong-rye as Hwang Ji-woo's mother (dream) (Ep. 15) == Ratings ==