Dr Seet was the Chief Medical Officer of the Singapore Armed Forces Medical Corps before joining the pharmaceutical industry in 1984 where he was Regional Director (Asia) for Medical and Regulatory Affairs and, for a time, concurrently Regional Director for Corporate Affairs for Ciba-Geigy (now part of Novartis). He subsequently was appointed a Vice-President, SmithKline Beecham International and General Manager of Tianjin SmithKline & French Labs based in Tianjin. He was, prior to joining Nanyang Technological University (NTU) in 1999, Managing Director (Greater China) of GlaxoWellcome China based in Shanghai. 

While in NTU, he was an Associate Professor in Entrepreneurship and Strategic Management in the Nanyang Business School and concurrently Deputy Director of The Nanyang Technopreneurship Center (NTC) and Managing Director of NTU Ventures Pte Ltd, the wholly-owned investment holding company of NTU. In NTC, he established the Minor in Entrepreneurship program. He also established and was the Founding Director of the highly successful Executive MBA program conducted by NTU at Shanghai Jiaotong University. 

Dr Seet has consulted for various institutional investors in evaluating investment opportunities especially in China in medical devices, pharmaceuticals, healthcare and education and training. He is also personally and actively involved in various bio-technology and educational start-up ventures. Dr Seet also speaks regularly at industry and policy forums.

Dr Seet was an Executive Director of Longlife Group Holdings Ltd, a company listed on the GEM board of the Hong Kong Stock Exchange (8037.HK).He was formerly Non-executive Chairman, Rockeby biomed Ltd, a company listed on the Australian Stock Exchange (RBY.AX) and an Independent Non-Executive Director of Jiwa bio-pharm Holdings Ltd, a company listed on the main board of the Hong Kong Stock Exchange (2327.HK).

Dr Seet is currently a Director at DM Capital and a Director in Harmony Master/Feeder Funds.