Jayakumar belongs to 1978 batch of IAS. He began his civil service career as an assistant collector in 1980. During his career Jayakumar held important bureaucratic positions at various levels in the Governments of Kerala and India, including District Collector, Kozhikode; Director of Tourism Department, Government of Kerala; Director of Public Instructions (DPI), Kerala;, Secretary, Tourism and Culture, Managing Director, Film Development Corporation, Joint Secretary, Ministry of Tourism & Culture, Government of India; Agriculture Production Commissioner, Government of Kerala. He served as the Chief Secretary, Government of Kerala during the period April 2012 to October 2012. In 2008, Jayakumar was honored by presenting the first K.P.S. Menon Memorial Award in recognition to his distinguished service as a bureaucrat. On retirement as the Chief Secretary, Jayakumar was appointed as the first Vice-Chancellor of the Thunchath Ezhuthachan Malayalam University
. Jayakumar is also a poet, lyricist, screenwriter and painter. He has written lyrics for nearly 100 Malayalam films and large number of songs for albums, Television and radio. He has also written and directed a children's film. He has held 17 solo exhibitions in India and abroad. He has authored twenty five books in Malayalam, and four works in English . His translations of Tagore, Kahlil Gibran and Rumi are well acclaimed.