Thondaman entered politics in 1985 and he entered the mainstream politics when he contested the
1994 general elections from the
Nuwara Eliya Electoral District representing the
United National Party and was elected to the
Parliament of Sri Lanka. He succeeded his grandfather Saumyamoorthi Thondaman as the leader of the Ceylon Workers' Congress party in 1999. He was consistently re-elected parliament in all elections held from 1994 to 2015, holding his parliamentary seat and the post of party leader until his death. He also served as a cabinet minister of UNP for a brief stint and joined the
Sri Lanka Freedom Party later in 2016. In December 2019, he was appointed as the cabinet minister of Community Empowerment and Estate Infrastructure Development by the Sri Lankan President
Gotabaya Rajapaksa. During his political career, he was well known for his long time alliance with former President
Mahinda Rajapaksa. He was due to contest at the upcoming parliamentary election representing
Sri Lanka Podujana Peramuna from the Nuwara Eliya district. ==Death==