Chen was the deputy speaker of the Hsinchu County Council from 1986 to 1994. The next year Cheng won a seat in the Legislative Yuan. He faced Lin Kuang-hua for the first time in the Hsinchu County magistracy election of 1997.[6] Cheng lost a contentious campaign, but managed to win reelection to the legislature in 1998. Shortly after the 1999 Jiji earthquake, Cheng supported the visit of Trinley Thaye Dorje, a Tibetan Buddhist leader, to Taiwan.[7] For a portion of his tenure in the legislature, Cheng served as Kuomintang caucus whip.[8] Cheng did not complete his second legislative term, as he was nominated the KMT candidate for the magistracy of Hsinchu County.[9] Subsequently, Cheng defeated Lin twice, serving as Hsinchu County Magistrate from 2001 to 2009.[10] In August 2006, the Hsinchu District Prosecutor's Office indicted Cheng on charges of bribery and corruption.[11] In light of the legal proceedings, his Kuomintang membership was suspended.[12] Cheng supported Chang Pi-chin, a former KMT member running an independent campaign for Hsinchu County Magistrate, in 2009.[13] As a result, Cheng's own
party membership was revoked.[2][14]
Cheng declared his independent candidacy for the 2014 Hsinchu County magistracy election, but lost despite the support of former rival Lin Kuang-hua and the Democratic Progressive Party.[10][15][16]
The next year, Chen launched an independent legislative bid for Hsinchu County Constituency, supported by the DPP and the Hsinchu County Cheng family political faction.[17][18] However, Cheng lost to Lin Wei-chou.[19]
