Born in his maternal ancestral home in the hamlet of Godigamuwa in Kalutara District, he received his basic education in the school of his home town, Wethara, and in 1947 entered Ananda College, Colombo, to complete his secondary education.
In 1961, he gained admission to Brighton Technical College, England, where he graduated as an electrical engineer in 1965 and returned home on April 23, 1965.
On May 17, 1965, he joined state service as an Assistant Electrical Engineer of Gal Oya Development Board stationed at Ampara.
While serving as the electrical engineer of CEB in August 1967, Dayaratna was elected as the President of the Mandala Mahaviharaya Buddhist Society of Ampara Town and under the guidance of Ven.
In February 1989 he was given the portfolio of Lands, Irrigation and Mahaweli Development and in April 1991 he was made the Minister of Rehabilitation, Reconstruction and Social Welfare.