He has served as Deputy Minister of Finance, chaired the Financial Supervisory Commission, and as an elected member of the Legislative Yuan.

[2] As deputy minister of finance, Tseng commented on the amendment to raise the tax and health and welfare surcharge on tobacco in early May 2013.

He stated that the move would result in a loss of NT$610 million in tax revenue but it will bring in an extra NT$25 billion in income used for health and welfare funds.

[3] He was named the Chairperson of the Financial Supervisory Commission of the Executive Yuan on 1 August 2013.

[4] Tseng was elected to the Legislative Yuan through the proportional representation ballot in 2016, as a member of the Kuomintang.