Career
Entering politics through students movements, he became the president of Progressive Students Union (PSU) in 1958. Later he enrolled as an advocate in Kollam Bar and was in active practice. Sivadasan got elected to the Kerala Legislative Assembly for first time in 1980 contesting as an RSP candidate.
He became elected in 1982 too as an RSP member.
In 1991, 1996 and 2001 he got elected again, contesting as a candidate of the Indian National Congress. Sivadasan was the minister for labour from 28 December 1981 to 17 March 1982 and minister for labour and excise during 1982-1987 in the ministries headed by K. Karunakaran.
He has served as Minister for Forests and Wildlife from 20 April 1995 to 9 May 1996 in the Ministry headed by A. K. Antony. Again he was the Minister for Electricity from 26 May 2001 to 11 February 2004 and held the portfolios of health and family welfare from 11 February 2004 to 29 August 2004 in the ministry, also headed by A. K. Antony.
Sivadasan is a senior congress leader and currently serving as DCC president of Kollam district, Kerala.
An active trade unionist, Sivadasan has served as Secretary of Kerala Provisional United Trade Union Congress in 1977, and participated in the International Labor Organization (International Labor Organization) conference in Geneva representing Central Government in 1985. He has also visited Italy, Switzerland, France, Germany and United Arab Emirates in various capacities.