Su Tseng-chang was appointed to the premiership on 14 January 2019 by President Tsai Ing-wen. He succeeded William Lai, who had resigned in response to the Democratic Progressive Party's poor performance in the 2018 Taiwanese local elections. This is his second tenure of premiership, as he had served as premier under President Chen Shui-bian from 2006 to 2007 with Tsai Ing-wen, the current president, as his deputy. At the age of 71, he is the third oldest individual to assume the office.

The 9th Legislative Yuan was a term of members of the Legislative Yuan of Taiwan, from 1 February 2016 to 31 January 2020. Members were elected in the 16 January 2016 legislative election. The ruling Democratic Progressive Party control the Legislative Yuan for the first time. The next legislative election was held on January 11, 2020 for the Tenth Legislative Yuan.