Lee Je-hoon began his acting career by appearing in several short and indie films. He came to limelight in 2011 when he starred in the movies Bleak Night and The Frontline, which scored him numerous Best New Actor trophies. In 2012, he landed a main role in the hit romance film Introduction to Architecture, which earned him a Best New Actor for Film nomination at the 48th Baeksang Arts Awards. In 2014, he took home a Top Excellence Award at the SBS Drama Awards for the sageuk Secret Door. In 2017, he led director Lee Jun-ik’s biographical period drama film Anarchist from Colony, in which he was nominated for Best Actor at the 26th Buil Film Awards and the 54th Grand Bell Awards. In 2018, he bagged a Top Excellence Award at the SBS Drama Awards for his performance in Fox Bride Star. In 2021, he portrayed an ex-convict looking after his nephew who has Asperger syndrome in the award-winning Netflix series Move to Heaven.

Lee Je-hoon studied biotechnology at Korea University but dropped out to pursue acting. He enlisted for his mandatory military service on October 25, 2012 and was discharged on July 24, 2014. In 2019, he co-founded the film production company called Hard Cut.