Chang was a member of the
Legislative Yuan from 1983 to 2000. As a legislator, he was Executive Director and General Convener of the DPP Caucus from 1987 to 1988, 1990, and 1998 to 1999. He was Convener of the Judiciary Committee in 1991, of the Home and Border Affairs Committee in 92, and of the Transportation and Communications Committee in 95. In 1994, Chang stood as the Democratic Progressive Party candidate to run for the mayor of
Kaohsiung, but was defeated by the Kuomintang incumbent
Wu Den-yih. In the
2000 presidential election he was General Manager of
Chen Shui-bian's campaign. In the Chen administration, he served as Secretary-General of the
Office of the President in 2000, Vice Premier of the ROC in 2000 and
Premier of the Republic of China from 6 October 2000 to 1 February 2002. From 2002, he was Secretary General of the Democratic Progressive Party and a senior adviser in the Office of the President. He ran in the
2004 Legislative Yuan election as fourth on the DPP's nationwide slate and was easily elected but resigned (as he promised to do during the campaign) since the
Pan-Green Coalition failed to win a majority. He also tendered his resignation as Secretary-General of the Democratic Progressive Party to take responsibility for the defeat. Chang was appointed the chairman of the
Straits Exchange Foundation in 2005 after the death of the former chairman
Koo Chen-fu. With the resignation of
Su Tseng-chang as Premier on 12 May 2007,
President Chen Shui-bian nominated Chang to fill the post of Premier a second time effective 21 May, and
Hung Chi-chang succeeded Chang as the chairman of the Straits Exchange Foundation. Su's resignation and Chang's second appointment as Premier marked the sixth premier that Chen Shui-bian has appointed during his two terms as President. ==Personal life and death==