[1] Rathnayake was born on 7 November 1947[2] in a small village near Kadugannawa as the fourth of the family with 10 siblings.
He was popularly known as Rathnayake Veda Mahaththaya, was an apothecary and sang "noorthi gee," a type of Sinhala folk songs.
[5] One of his elder brothers, Victor Rathnayake is a renowned musician in Sri Lanka.
[10] On 6 April 2020, Jayantha Rathnayake died at the age of 52 while receiving treatments at Apeksha Hospital, Maharagama.
He started to play cello under the guidance of M. K. Rocksamy and then from Miss Joyce at Ceylon Symphony.
[5] Rathnayake joined cinema as a backing violin player under Khemadasa for the film Hanthane Kathawa directed by Sugathapala Senarath Yapa in 1969.
[14] Rathnayake was the music director for many films directed by Gamini Fonseka such as Uthumaneni, Sagarayak Meda, Koti Waligaya and Nomiyena Minisun.
[14] He was the music director for all the films directed by Dinesh Priyasad including, Demodara Palama and Peralikarayo.
Jothipala has sung to his music in many films such as Ridee Thella, Waradata Danduwam, Paaradise and Peralikarayo.
Rathnayake's maiden cinema acting came through the 1992 film Raja Daruwo directed by Daya Wimalaweera.
[4] For that film, he composed the popular song Dilidune Daruwane Mage sung by Gratien Ananda.
His song Muhuda Mage Goda Bimai in the cartoon "Dosthara Honda Hitha" gained large popularity.