Lee Jung-jae started out as a model before debuting as an actor in the 1993 SBS series Dinosaur Teacher. In 1995, he starred in the iconic television drama Sandglass, which won him Best New Actor at the SBS Drama Awards and the 31st Baeksang Arts Awards. In 1995, he took home several Best New Actor trophies for the film The Young Man. In 1999, he led the movie City of the Rising Sun along with Jung Woo-sung. His work in the film won him two Best Actor awards. In 2011, he was named Best Actor at the 31st Fantasporto Director’s Week for the erotic thriller The Housemaid. In 2013, he appeared in the box-office hit The Face Reader, in which he took home several Best Supporting Actor awards. In 2015, he bagged another Best Actor trophy at the 24th Buil Film Awards for his performance in the espionage action film Assassination. In 2021, he gained international fame and acclaim after starring in the megahit Netflix survival drama Squid Game.

Lee Jung-jae is close friends with his City of the Rising Sun co-actor Jung Woo-sung and co-owns several businesses with him. In January 2015, he went public with his relationship with heiress Im Se-ryung. He also dated actress Kim Min-hee in the past.