[1] Guneratne, like his grandfather E. B. Wikramanayake, was educated at S. Thomas' College, Mt Lavinia.
He was Head Prefect of the College (1976) and was a member of the English Debating and Drama Societies, a Junior Librarian, Co-Editor of the College Magazine (with Chanaka Amaratunga and Richard de Zoysa, Leader of the Classical Quiz competition team (with Rohan Edirisinghe, Richard de Zoysa Uthum Herat, Chanaka Amaratunga and Devaka Fernando),[3] a member of the Science Quiz team which reached the semi-finals of the national competition (with Uthum Herat Professor Chandu de Silva and Devaka Fernando), Tent Secretary of the Royal-Thomian Tent Committee and President of the Photographic Society.
[6][7] After retirement from competition he went on to serve the Sri Lanka Chess Federation as Secretary and Vice President.
Guneratne also served in similar capacities to the Chess Association of Sri Lanka in which he was a founder member.
In 1995, he moved to Spring Hill College, Mobile, Alabama, where he was promoted to Associate Professor.