Early Although he had little formal education, knowing his abilities in mathematics, Puthukkada Chettiyar, a wealthy merchant, appointed Kesava Pillai as his accountants Later he was appointed as the apprentice of Pokkumoosa Marickar, a leading merchant and exporter. Pokumoosa was very faithful to the Maharaja of Travancore, Karthika Thirunal Rama Varma and during a visit to his palace Kesava Pillai accompanied him.
The maharaja was impressed by the skills of Kesava Pillai and he was appointed to the Travancore palace.
When Tippu Sultan of Mysore attacked Travancore, Kesava Pillai was the commandant of the state army.Travancore army fought against the Mysore force under the leadership of Kesava Pillai and Tippu was forced to retreat. Recognizing his victory over the Mysore, the Karthika Thirunal Maharaja of Travancore appointed Kesava Pillai as Diwan of Travancore.
He was glorified by the British Governor Mornington, by the title Raja in appreciation of his administrative talents.As Diwan, Raja Kesavadas was responsible for shifting the capital of Travancore from Padmanabhapuram to Thiruvananthapuram. His tenure of Diwan ended with demise of Dharma Raja Karthika Thirunal in 1798.
Balarama Varma, his successor aged fourteen became the crown prince who was a puppet in the hands Jayanthan Sankaran Nampoothiri.
Raja Kesavadas was proclaimed as a traitor and kept under house arrest which helped Jayanthan Sankaran Nampoothiri to usurp the post of Diwan. Later his family assets were confiscated and was poisoned to death on 21 April 1799.