Ryu Joon-yeol made his feature film debut in the 2015 thriller drama film Socialphobia. His work in the movie earned him numerous acting awards, including the Best New Actor trophy at the 11th Max Movie Awards. That same year, he starred in the hit tvN series Answer Me 1988, which won him Best New Actor at the 52nd Baeksang Arts Awards. In 2016, he was paired with Hwang Jung-eum in the MBC romantic comedy Lucky Romance, in which he was once again named Best New Actor, this time at the 36th MBC Drama Awards. In 2017, he took home the Best New Actor for Film honors at the 53rd Baeksang Arts Awards for his performance in the movie The King. Also in 2017, he appeared in the film A Taxi Driver, which scored him acting nominations at the 38th Blue Dragon Film Awards and the 23rd Chunsa Film Art Awards.

Ryu Joon-yeol enlisted for his mandatory military service in 2007 and was discharged in 2009. He dated his Answer Me 1988 co-star Hyeri for six years.