He was National Security Advisor of India from 2005 to 2010, assuming the role after the demise of his predecessor Jyotindra Nath Dixit in January 2005.

Their son-in-law Ajit Nambiar is Chairman and Managing Director of BPL Ltd.[7] M. K. Narayanan joined the Indian Police Service in 1955 and passed out with the highest marks.

After a brief stint as Sub-Divisional Police Officer in the erstwhile State of Madras, he went on deputation to the Intelligence Bureau in February 1959.

The rest of his service career was spent under the Government of India, mainly in the Intelligence Bureau, in which he dealt with a whole range of issues concerning internal and national security.

He took over as Governor of West Bengal from Gopalkrishna Gandhi, who had a few disagreements with the then CPI(M)-ruled state on critical issues like violence in Nandigram and Singur.