Born at the Dassanayake Walawwe in Mirigama to Lois Robert Clifton Dassenaike and Amybelle Charlotte Valerie née Corea, she was educated at Ladies' College, Colombo, where she was a hostel prefect and sports captain.
James Obeyesekere would serve as the Parliamentary Secretary of Health and Finance, thereafter he was appointed to the Senate of Ceylon in 1965.
[1] When James Obeyesekere was the member of parliament for Attanagalla from 1960 to 1965, Siva Obeyesekere organized community health programmes in 127 villages in the Attanagalle electorate and actively began to develop handicraft and handloom centres.
In 1964, she started the Laksala, which was the first Government Cottage Industries Emporium and became the chairman of its advisory board.
[1] She contested the Mirigama electorate in the 1965 general election from the Sri Lanka Freedom Party and won the seat defeating Wijayabahu Wijayasinha and entered parliament.
Senator Edward Kennedy gave her a special award of appreciation for her efforts.