Born on December 5th 1941 in Gampaha district. Started practising in Kanduboda at the age of 15. He received his samanera (novice) ordination in 1963, his upasampada (bhikkhu) ordination in 1965. In 1969, he obtained official Burmese Master's recognition as a meditation teacher and later on also as a teacher of meditation teachers.

On passing away of his beloved teacher ven. Sumathipāla in 1982, ven. Pemasiri became the chief incumbent of the center. After 5 years of untiring work, he relinquished this position and spent about a year abroad learning and travelling. Some time after returning to Sri Lanka, he became the chief incumbent at the Lanka Vipassanā Centre in Colombo, where stayed for 12 years. After about a year's stay in Australia he was invited to come to Kanduboda and start a new place on the original center's lands. He is currently still the abbot at the Sumathipāla Nāhimi Senasun Arana.