Jang Kwang first established himself as a talented voice actor before expanding his career to the screen. In 2011, he caught viewers’ attention with his dual role in the crime-drama film Silenced. In 2012, he played a loyal eunuch in the period drama Masquerade, which was named Best Film at the 49th Grand Bell Awards and the 49th Baeksang Arts Awards. That same year, he appeared in the film 26 Years and then in Secretly, Greatly and in New World in 2014. He also joined the main cast of the 2014 tvN body swap comedy series Flower Grandpa Investigation Unit. In 2017, he acted alongside Lee Seung-gi and Cha Seung-won in the high-rating tvN fantasy drama Hwayugi. Also in 2017, he portrayed the God of Violence Hell in the box-office hit action fantasy Along With the Gods: The Two Worlds. In 2018, he starred in the movie 60 Days of Summer. In 2021, he was cast as one of the main characters in the KBS2 sageuk Moonshine.

Jang Kwang is married to actress Jeon Sung-ae. Their daughter Jang Yoon-hee, also known as Mija, is a comedienne.