Samarasinghe joined the Sri Lanka Freedom Party in 2006 and is the Sri Lanka Freedom Party chief organiser for the Agalawatta Electorate in Kalutara District. He had also served as Cabinet Minister of Disaster Management and Human Rights from 2006 - 2010 and Minister of Plantation Industries from 2010 - 2015. He was a member in the Parliamentary Consultative Committees of the Ministries of Trade, Commerce, Industries, Finance and Foreign Affairs. Samarasinghe is married and has four  children.