Prof. Tilak P D Gamage graduated from University of Ruhuna in 1992 and obtained his master's degree in environmental sciences in 1996. He subsequently entered the Graduate School of Science and Engineering at Saitama University Japan to pursue a PhD in Environmental Engineering. After completing the PhD in 2000, he served as an Invited Research Fellow at the laboratory for a year. Upon returning to Sri Lanka in 2001, he joined the Faculty of Science at University of Ruhuna as a Senior Lecturer. He continued to maintain a strong alliance with his colleagues in Japan as Japan Society for Promotion of Science (JSPS) Fellow in 2005/2007, and Japan Student Services Organization (JASSO) Fellow 2008. Furthermore, in 2007 Prof. Tilak P D Gamage became a respected member of the Faculty of Fisheries and Marine Sciences & Technology. In 2011, he obtained a diploma in International Environmental Law from the United Nations Institute for Training and Research (UNITAR), Switzerland.
Prof. Tilak P D Gamage served as the Dean of the Faculty of Fisheries and Marine Sciences & Technology at University of Ruhuna throughout 2008 to 2014. As the faculty was founded in 2005, he overcame substantial challenges to establish this new faculty by acquiring buildings and other infrastructure. In the University, he served in many other positions, including Director of the Center for International Affairs (CINTA), Project Director of the University of Ruhuna Township Development Project, Editor-in Chief of the University of Ruhuna Highlights newsletter, and Chairman of the Sports Advisory Board. He is the current co-director of the China-Sri Lanka Joint Center for Education and Research (CSL CER) which was established through his close collaborations with South China Sea Institute of Oceanology of Chinese Academy of Sciences. He played a key role in instituting a master's degree programme in partnership with University of Chinese Academy of Sciences.
Prof. Tilak P D Gamage is a recipient of the Vice Chancellor's Award for the Most Outstanding Convener of the International Conferences and Promoter of International Relations 2014. In recognition of his extensive involvement to promote international affairs, he was also awarded the prestigious Guangdong Provincial Science and Technology Cooperation Award 2019 which is an esteemed international cooperation award in Guangdong Province, China.
In 2004, Prof. Tilak P D Gamage was appointed as a member of the Board of Directors of the National Institute of Fisheries and Nautical Engineering (NIFNE). He was also the President of the Sri Lanka University Sports Association (SLUSA) from 2017 to 2020.
Prof. Tilak P D Gamage has a keen interest in quality assurance of higher education. He served as the Director of the Internal Quality Assurance Unit of the University of Ruhuna from 2015 to 2019.