Kasun was born in Rajagiriya, Sri Lanka on 3 November 1981. His mother, Malani Bulathsinhala, was a veteran vocalist and his father H. M. Jayawardena was a renowned composer. He had a younger sister, Nirmani Chaya who died in 1991 at the age of three.

 

Kalhara's music career started along with Indrachapa Liyanage and his schoolmates from Ananda College in the year 2000. His mother was highly supportive of his musical career. Once a newspaper interviewer asked her "what is the most memorable day in your life?" and she answered "the day Maestro Premasiri Khemadasa hugged and wished my son Kasun Kalhara, following his first musical concert (Waves of Introspection). That warm hug from Maestro Kemadasa guaranteed that Kasun had a genuine talent and a clear future".

 

Kasun has held a number of solo concerts, collaborating with other artists such as "Kasun Kalhara: Live in Concert", "Kasun Kalhara Unforgettable Live in Concert", "The Black Red White Concert", "Kasun Kalhara in Culture Shock", "4U: Live in Concert" and "Love U: Live in Concert".

 

Kasun Kalhara performed in Culture Shock (2013) and Kasun Kalhara in LoveU (2016/2017) Those three concerts became one of the most attended musical shows in history of Sri Lanka with over 5,000 fans gathering around at the Nelum Pokuna Mahinda Rajapaksa Theatre for all the three events.