Cho Jin-woong (born Jo Won-joon on April 2, 1976) is a South Korean actor. He is best known for his roles as Sejong's loyal bodyguard in Deep Rooted Tree (2011), a mobster in Nameless Gangster: Rules of the Time (2012), and a mysterious villain in A Hard Day (2014). He also gained recognition and praise for his performance as a detective in the television series Signal (2016).