In 1989, Mangala Samaraweera entered Parliament representing the Matara District, in 1994 in the cabinet of President Chandrika Bandaranaike Kumaratunga was Minister of Post & Telecom. Also served as the Minister of Urban Development, Construction and Public Utilities. After a reshuffle in the same Cabinet was given the Deputy Minister of Finance portfolio. In 2004 in the new cabinet of President Chandrika Bandaranaike Kumaratunga was the Minister of Ports, Aviation and Media.
Latter was campaign manager for the new Presidential candidate and Prime Minister Mahinda Rajapakse, surprised many by appointing Samaraweera to the post of Foreign Minister. Samaraweera falling out with the president Mahinda Rajapaksa in 2007.
During 2015 Presidential election, he played a pivotal role as a joint spokesperson of the opposition coalition candidate Maithripala Sirisena. In January 2015, the new President Maithripala Sirisena appointed Samaraweera as the Minister of Foreign Affairs and latter was the Finance Minister.
Samaraweera resigned from the position of Finance Minister as of 17 November 2019 hours prior to release of the general election results. After the 2019 Presidential election, joined newly formed Samagi Jana Balawegaya in 2020 led by the present opposition leader Sajith Premadasa.
Today the country has lost a true people’s representative of our time, talented and loved by all. In 1983, he entered active politics as the Matara Sri Lanka Freedom Party chief organiser. After three decades in active politics on 9 June 2020, a true Royalist he was, Mangala Samaraweera announced that he would step back and quit parliamentary politics not seen often from senior politicians in our country!