Kim began his career as a fashion model and made his acting debut in the coming-of-age film Just Friends? in 2009 under the stage name Seo Ji-hoo. It was in 2014 when he started taking on lead roles in various genres and has seen a rising popularity.
“I Wanna Hear Your Song” is a mystery romantic comedy about a timpanist Hong Yi-young and suspicious tone-deaf pianist Jang Yoon. Yi Young suffers from insomnia after getting traumatized by what happened on ‘the day’ and comes across Yoon who helps her remember. They try to put Yi Young’s forgotten memories together and the truth about the murder case that traumatized Yi Young.