* Lee Seung-gi as Choi Kang-chi / Gu Wol-ryung
* Bae Suzy as Dam Yeo-wool
* Lee Sung-jae as Gu Wol-ryung
* Sung Joon as Jo Gwang-Woon
* Yoo Yeon-seok as Park Tae-seo
* Lee Yoo-bi as Yoon Seo-hwa
* Kim Hee-won as Gon
* Um Hyo-sup as Yoon Seong-mo
* Kim Dong-hwi as young Choi kang-chi
* Jung Yoo-jin as young Dam Yeo-wool
* Han Da-min as young Yoon Seo-hwa
* Jo Min-ki as Park Chung-jo