Byun Yo-han made his acting debut in 2011 through appearances in short films. He gained prominence with his supporting role in the 2014 tvN workplace drama Misaeng, in which he bagged the Best New Actor trophy at the 4th APAN Star Awards. The following year, he headlined the indie film Socialphobia, which won him Best New Actor at the 24th Buil Film Awards. His work in the movie also earned him Best New Actor nominations at the 51st Baeksang Arts Awards and the 36th Blue Dragon Film Awards. Also in 2015, he was cast as one of the six leads of the SBS sageuk Six Flying Dragons, which gave him a Best New Actor for TV nomination at the 52nd Baeksang Arts Awards. In 2018, he became part of the hit tvN drama Mr. Sunshine. In 2021, he was nominated for the Baeksang Best Actor award for his performance in the black-and-white historical biopic The Book of Fish. The movie was his first project after his two-year acting hiatus.

Byun Yo-han enlisted for his mandatory military service in 2006 when he was 20 years old.