Hong Kyung made his acting debut in 2017 with a small role in the KBS2 series Mystery Queen. That same year, he acted alongside Gong Myung and Kim Jae-young in the web drama Brain, Your Choice of Romance. In 2020, he landed his first big screen role in the crime drama film Innocence, which won him Best New Actor at the 57th Baeksang Arts Awards. He later starred in the indie movie A Distant Place, which earned him a Best New Actor nomination at the 30th Buil Film Awards. In 2021, he played supporting characters in the Netflix military series D.P. and in the SBS sageuk Lovers of the Red Sky. In 2022, he joined the main cast of the Wavve drama Weak Hero Class 1.

Hong Kyung majored in theater and film at Hanyang University.