[2] Born at Waragoda, Kelaniya, he was the eldest male child of ickremaratchi Imia Rajakaruna Liyana Atukoralage Don Daniel Jayatilaka Senanayake Liyana Aratchi of Pattalagedera, Veyangoda, a government servant, and his wife Liyanage Dona Elisiana Perera Weerasinghe, daughter of oriental scholar, Don Andiris de Silva Batuwantudawe of Werahena, Bentota.

[3] When he was seven years Jayatilaka was sent to the Vidyalankara Pirivena, where he learned Sinhala, Pali and Sanskrit by Ratmalane Sri Dharmaloka Thera.

[4][5] He first met Colonel Henry Steel Olcott in 1890 and joined his campaign to establish English medium Buddhist schools in the country.

He was instrumental in the establishment of the Young Men's Buddhist Association (YMBA) at Borella becoming its President in 1898 and holding the post until his death.

Soon after his release he left for Britain where he campaigned to end the injustices in Ceylon and agitated for a Royal Commission to investigate the 1915 riots.

Following the constitutional reforms of the Donoughmore Commission, Jayatilaka was elected to the newly formed State Council of Ceylon from Kelaniya in 1931.

During World War II, he helped organise volunteers to unload food from ships at the Colombo harbour after it was deserted following Japanese air raids.

[7] Sir Baron Jayatilaka was appointed a Knight Commander of the Order of the British Empire (KBE) in the 1943 Birthday Honours while he served as the representative of the Ceylon Government in India.

[10] Sir D. B. Jayathilaka served as the president of Young Men's Buddhist Association for a continuous period of 46 years, from 1898 until his death in 1944.

Under his influence Colombo YMBA inaugurated a program for promoting 'Dhamma School education', with the obligation of giving every Buddhist child in Ceylon the gift of Dhamma”.