He rose to fame in the 2007 television drama First Wives' Club, and has since played leading roles on The Road Home (2009), Don't Hesitate (2009), Life Is Beautiful (2010), and Feast of the Gods (2012).

This was followed by more supporting roles on television, including his big screen debut in Almost Love, a romantic comedy film headlined by Kwon Sang-woo and Kim Ha-neul.

In the same year, he also appeared as one of the leading actors in Searching for the Elephant, an erotic-psychological thriller about three thirty-something men struggling with schizophrenia, sex addiction and infidelity.

[7] Despite the controversy, the show was successful in the ratings,[8] and Lee would later work again with renowned screenwriter Kim Soo-hyun on A Thousand Days' Promise (2011) and Childless Comfort (2012).

[13][14] Unlike his previous calm and quiet roles, in 2014 he was cast as the leading man in Glorious Day, a peculiar character which Lee said he looked forward to playing since it most resembles his real-life personality.