Answer
Moon Jae-in was imprisoned under the presidency of Park Chung-hee. He was arrested for his involvement in the 1980 Gwangju Uprising, a popular uprising against the military dictatorship of Chun Doo-hwan. Moon was sentenced to 20 years in prison, but was released after serving just three years. He has since become a prominent figure in South Korean politics, and was elected president in 2017.