Dr. Sansern first became a Member of Parliament as a Democrat's party list in 2001. He was elected MP for Din Daeng, Huai Khwang and Lat Phrao Districts of Bangkok in 2007, and again in the 2011 election for Lat Phrao and Wang Thonglang Districts, Bangkok.
His past functions at the Democrat Party include Deputy Spokesperson; Vice Chairman of the Economics, Monetary, Finance, Banking and Financial Institutions Commission of Parliament; and Deputy Party Chief under the new leadership of Mr. Jurin Laksanawisit.
Dr. Sansern has been active in both district and national agendas. He is well known for closely ccoperation with officials of the Lat Phrao and Wang Thonglang districts to combat the major floods in 2011, and has remained vigilant in the upkeep of roadways and drainage systems in the area ever since. He also initiated a mobile medical unit for residents' assistance. His work in the area also includes providing assistance with locating temporary venues for retailers of inexpensive goods, and finding ways to discourage illegal drug trade and use. Nationally he has played significant roles in the drafting of policies and laws to benefit Thai citizens including ones for free education, free medical assistance, monetary assistance for seniors, and government partnership with private businesses in retirement funds for workers.
His career expertise include a World Bank Economist position at the Thai Ministry of Finance, and adjunct instructor for graduate courses at the Department of Banking and Finance, Chulalongkorn University. He has authored several papers including The Relationship Between National Deficits, Government Investments, and Private Investments in Thailand, which was published in the Journal of Asia Pacific Economy.
His education history includes primary and secondary school at Kasetsart University Laboratory School; preparatory school at Triam Udom Suksa School; Bachelor of Commerce and Accountancy (Cost Accounting) from Chulalongkorn University; Master of Economics (Finance) and Ph.D. in Economics (Monetary Policy and Asian Economic Development) from Claremont Graduate University, CA USA.
Dr. Sansern is the eldest son of former Bangkok Metropolitan Administration's Permanent Secretary Mr. Prasert Samalapa and Mrs. Sunanta Samalapa.