Born on 17 September 1940 in the south Indian state of Tamil Nadu, Paramasivam Natarajan graduated in chemistry from the University of Madras in 1959. He started his career as a lecturer at the Government Arts College of the Madras University in 1959 but later moved to the NGM College, Pollachi in 1963. The next year, he joined the Banaras Hindu University (BHU) as a CSIR Junior Research fellow and during the tenure of the fellowship, obtained his master's degree in 1963. After continuing at BHU for a year more, he became a lecturer at the Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) where he stayed till 1970. Later he went to the US as a teaching assistant at the University of Southern California, simultaneously pursuing his doctoral studies under the guidance of John F. Endicott. He secured a PhD in 1971 and did his post doctoral studies under his PhD guide, Endicott, at Wayne State University as the latter had moved to the Michigan-based university by that time.
Natarajan returned to India in 1974 and joined his alma mater, Madras University, as a reader of the department of physical chemistry. In 1977, he became a professor in charge of the Post Graduate Centre of the university in Tiruchirappalli. In 1982, he returned to the university headquarters in Chennai as the head of the department of inorganic chemistry. In 1991, he was deputed by the university as the director of Central Salt and Marine Chemicals Research Institute (CSMCRI), a post he held till 1996. After the completion of the assignment at CSMCRI, he resumed his duties at the university and became a senior professor in 1998. At time of his superannuation in 2001, he held the post of an INSA Senior Scientist at the National Centre for Ultrafast Process of the university and served as a member of the university syndicate.
Natarajan was married to Sivabagyam and the couple had two daughters, Shiva Sukanthi and Shakthi. He died on 18 March 2016, at the age of 75, survived by his wife, children and their families.