黨外運動
A lawyer, Chen entered politics in 1980 during the Kaohsiung Incident as a member of the Tangwai movement and was elected to the Taipei City Council in 1981. He was jailed in 1985 for libel as the editor of the weekly pro-democracy magazine "Neo-Formosa", following publication of an article critical of Elmer Fung, a college philosophy professor who was later elected a Kuomintang legislator. After being released, Chen helped found the Democratic Progressive Party (DPP) in 1986 and was elected a member of the Legislative Yuan in 1989, and Mayor of Taipei in 1994.