His father, L. M. Tennekoon, was a popular local poet who practised indigenous medicine and astrology.
In 1934, he started his own printing press, writing poems and verses, and publishing short poetry books, such as Ruwanweli Maha Sea Varnanaya (Narration of Ruwanweli Maha Seya), Sri Gouthama Vama Dalada Vandanava (Pilgrimage of Sri Gouthama left tooth Relic), Ruwanveli Vandanava (Ruwanweli Pilgrimage) and Vessanthara Sinduwa (Vessanthara Songs).
In 1956 Tennekoon contested the seat of Dambulla at the 3rd parliamentary election, held between 5 and 10 April, representing the Mahajana Eksath Peramuna (People's United Front).
[6] He was subsequently appointed Parliamentary Secretary to the Minister of Transport and Works in the Sirimavo Bandaranaike cabinet.
[4] In 1963 when he was appointed, Parliamentary Secretary to the Minister of Education & Cultural Affairs in the Sirimavo Bandaranaike cabinet first re-shuffle.