Chandrasena was impressed by Walpola's ability to sing and after auditioning several songs with harmonium accompaniment, sent a good word to the Radio Ceylon broadcaster Thevis Guruge.
From his debut to the early 1960s, Walpola dominated male playback singing in Sri Lankan cinema providing a counterpoint to the harsh Carnatic style of Mohideen Baig with his softer more melodic voice which lend itself to love songs.
His best known work from this period include "Seeya Manamalaya" from Asoka (1955), "Amu Pitisareyeki" from Seda Sulang (1955), "Upatha Labaa" and "Suba Aasiri (Hanika Yamang)" from Mathalang (1955), "Surathalee" from Surathalee (1956), "Katey Kiri Suwanda" from Sandesaya (1960), "Oya Belma" and "Waththe Wetunu Pol Athu" from Kurulu Bedda (1961) and "Man Mula Wela" from Deepashika (1963).
Walpola's dueting partners included Vivienne de Silva Boralessa, Chitra Somapala ("Pem Suwandai") and Rukmani Devi in addition to Latha.
Walpola successfully returned to Radio Ceylon with "Uthama Muni Dalada" (lyrics by Ajantha Ranasinghe and music by Sanath Nandasiri.
His mother was Mrs Karunawathie and father Mr Charles Appuhamy, a dressmaker by profession, tailored costumes to the Tower Hall artists.
Mathalang, Surathalee, Sukomali, Surangani, Asoka, Suhada Sohoyuro, Suraya, Surasena, Sundara Birida, Sithala Watura, Deevaraya, Veera Vijaya, Radala Piliruwa and Dostara (Doctor) were a few among hundreds of movies that captured hearts of the people with his exhilarating voice.
Unfortunately this golden voice withered away with his final song "Asha Mal Pawan" in film "Samanmalee" released in January, 1979 to the Sinhala Cinema.
The song "Kowlan Handaine" and "Amba Damba Sevanali" sung with Sydney Attigala for the film "Jeevithaya" are still a hot favorite among the public.
Pathiwatha, Veeravikrama, Ahinsaka Prayogya, Angulimala, Sudu Nangi, Ley Kandulu, Shimbo, and Anjalee are clear testimony to his masterly vocal performance.
His masterly performance of singing in Bari Sil, Kela Mal and Nawarella, famous ballet music composed by Musician Dr Premasiri Khemadasa captured the fully packed spell bound audience at every presentation.
Among the songs recorded were "Sansare Duka Nesu Shakya Raja", "Ananda Javanika", "Ase Gethe Madura Geethe" with Rukmani Devi, "Sri Lankave Shantha Sobana", "Dakina Dakina Wele", "Manike Manike Run kande", "Suwanda Gange Adere Ape" with Latha and solo like "Me Prema Kathawe" These songs became highly popular overnight.
He shared his golden voice with Latha, G.S.B.Rani Perera, Rukmani Devi, Viviene de Silva Boralessa, Chitra Somapala, Nanda Malini, Sujatha Aththanayake, Jikki, K. Jamuna Rani et al.
He has sung under the directors Mohammed Gausse, R. Mutthusami, B. S. Perera, Sunil Shantha, R. A. Chandrasena, P. L. A. Somapala, Premasiri Khemadasa, Sarath Dassanayake and Sanath Nandasiri.
Also he recorded songs under the direction of famous Indian musicians as Dakshina Murthi, S. S. Weda, T. R. Papa, R. Sundaram, Raja Thangendra, Gowradanam and Jayadev.
His fans and friends, including Vernan De Silva, organised a Commemorative Death Anniversary Celebration in Kandy as a tribute to this versatile play-back singer with meritorious deeds of blood donation program, Sangika Dana, launch of a book written on Dharmadasa’s biography and issue a commemorative stamp to coincide with the thirtieth anniversary of his death.