Apart from his university activities, Prof. Disanayaka has played a major role, in the advancement of scholarship, Buddhism and culture by taking an active part in many international conferences, seminars and institutions concerned with such pursuits. He has delivered many guest lectures and endowed orations. As a scholar Prof. Disanayaka has gained both national and international recognition and prestige too, for his excellent scholarship and academic contributions.

The international positions offered to him include: Senior Fellow in the Department of Indology, School of Oriental and African Studies (SOAS), UK (1992-93); Visiting Professor, Wako University, Japan (1998); Ambassador of Sri Lanka in Thailand (2007-2011). He has also won four State Literary Awards for his academic publications by the government of Sri Lanka. In 1996, he received the National Award of Sarvodaya Trust Fund for the advancement of humanity, peace and development. In recognition of the eminence he has attained in the field of linguistics and Sinhala grammar, and his distinguished contributions to the advancement of knowledge, in 2003, the University of Colombo conferred the honorary degree of Doctor of Letters (D.Litt). He received the title of Kirti Sri from the University of Sabragamuwa. In 2005, he was awarded the coveted presidential honorary title Desamānyafrom the Government of Sri Lanka, in recognition of his services to the country.