Lee Seon-kyun began his acting career in 2000 with the short film Psycho Drama, which was followed by his stage debut in the musical The Rocky Horror Show in 2001. His career breakthrough came in 2007 when he was cast in back-to-back successful MBC dramas, namely White Tower and Coffee Prince. The former gave him a Golden Acting Award at the MBC Drama Awards. In 2009, he starred in the film Paju, which won him Best Actor at the 11th Las Palmas de Gran Canaria International Film Festival. In 2010, he was paired with Gong Hyo-jin in MBC’s Pasta, which earned him a Top Excellence Award nomination at the MBC Drama Awards. In 2012, he was nominated for another Top Excellence Award at the MBC Drama Awards for the medical series Golden Time. In 2014, he led the action thriller film A Hard Day, which scored him the Best Actor trophy at the 51st Baeksang Arts Awards. In 2018, he acted alongside IU in tvN’s My Ajusshi, which was named Best Drama at the 55th Baeksang Arts Awards. In 2019, he was launched into international fame for his starring role in director Bong Joon-ho’s acclaimed black comedy thriller film Parasite. The movie bagged numerous accolades, including Best Picture, Best Director, Best Original Screenplay, and Best International Feature Film at the 92nd Academy Awards.

Lee Seon-kyun graduated from Korea National University of Arts with a Bachelor of Fine Arts in Acting. In May 2009, he married actress Jeon Hye-jin. On December 27, 2023, he was found dead in his car in central Seoul. He was facing police investigation over suspected drug use at the time of his death.