He was elected to the Kerala Legislative Assembly from Mattanur constituency in Kannur district and is a member of the Communist Party of India (Marxist).

Jayarajan was born on 28 May 1950 at Irinave village in Madras State (present-day Kannur district), India, as the son of B. M. Krishnan Nambiar and E. P. Parvathi Amma.

(Democratic Youth Federation of India) and was the General Manager of the CPI(M) party mouthpiece Deshabhimani.

He was the President of Kerala Karshaka Sangham and Central Committee Member of Communist Party of India (Marxist).

[4] On 14 October 2016, he resigned over nepotism following allegations that he appointed his own family members as heads of public sector undertakings in the state.