He has also acted on several occasions in addition to his duties, in the post of Secretary to the Ministry of Defence and External Affairs and Secretary to the Ministry of Trade and Shipping. He has at various times been the Chairman of the National Institute of Education; Chairman, Board of Management of the Sri Lanka Institute of Development Administration; Chairman of the - Agrarian Research and Training Institute; Chairman of the Public Sector Infrastructure Development Company; Chairman of the National Development Trust Fund, Chairman and Director General of Broadcasting; The Executive Vice Chairman - Sri Lanka National Commission for U. N. E. S. C. O. and Chairman of The National Eisenhower Award Nomination Committee on the Invitation of the Ambassador for the United States of America and Chairman S. W. R. D. Bandaranaike National Memorial Foundation Board which governs the B. M. I. C. H., the B. C. I. S. and The Sirimavo Bandaranaike Convention Hall.
He has also served on the Governing Councils or Boards of Management in several Universities and Post Graduate Institutes, including the council of the University of Colombo; the Board of Management of the Post Graduate Institute of Medicine; the University of Colombo School of Computing; the Council of the Buddhist and Pali University; The Board of Management of the Arthur C. Clarke Centre of the University of Moratuwa; the Post Graduate Institute of Archaeology of the University of Kelaniya and The Post Graduate Institute of Management of the University of Sri Jayawardanapura. He has been a Director at People’s Bank, the People’s Merchant Bank, Merc Bank and a Member of the Rural Credit Advisory Committee of the Central bank. He has also from time to time served on the Governing Boards of the National Institute of Plantation management; of The National Human Resource Development Council; The Ceylon Shipping Corporation; The Cooperative wholesale establishment, Sri Lanka film corporation; National Education commission; The Sri Lanka Foundation Institute; The National Committee on Women; The National Council for Elders; Mahapola Higher Education Scholarship Trust; The National Institute of Social Development; Member Board of Trustees of the Tower Hall Foundation; Member Advisory Committee on Regional Cooperation in Education in Asia and the Pacific appointed by the Secretary General of U. N. E. S. C. O; Governor for Sri Lanka on the Governing Board of the S. A. A. R. C. Centre for Human Resource Development - Islamabad, Pakistan. He led the Sri Lanka Delegation to the 51st E. S. C. A. P. meeting of ministers held in Bangkok, Thailand in 1995 and was elected a Vice President of the meeting in which role he chaired the ministerial meeting on occasion and was also elected as a member of the Credentials Committee.
He has also lead the Sri Lanka delegation to the Annual Sessions of U. N. E. S. C. O. in Paris and been a Senior member of delegations to the non aligned conference in Colombo and to ministerial meetings of agriculture at F. A. O. in Rome and of Commonwealth Education ministers in Barbados and Islamabad. He has also been either leader or Senior member of various official delegations on the subjects of ffood; agriculture; trade; education; and public administration and Governance for meetings held in the U. S. A., Britain, France, Germany, Sweden, Norway, Switzerland, Australia, India, Pakistan, China, Malaysia, Singapore, Thailand, Indonesia, Burma, The Philippines, Japan, Egypt, The Soviet Union, South Korea, Libya, Italy, Mexico, Barbados and Canada.
He has served as a Member of the National Salaries Commission; a Member of the Presidential Commission on Finance and Banking and has chaired three presidential committees-one to examine and report on the proposed mechanised gem mining in the Kalu Ganga; the other on the Functioning of the Survey Department, and the third on the Sri Lanka Foreign Service. He was a member of a Presidential committee tasked “To identify and study the problems of the university system and to make recommendations”. He was a member of a senior officials committee appointed by the Cabinet and Chaired by the Governor of the Central Bank tasked with producing a report on the overall subject of poverty alleviation. This report was termed the Janasaviya report and formed the basis for setting up the Janasaviya Trust.
He was a member and later Chairman of the Panel of Legal/Constitutional experts appointed by the President to serve the National All Party Conference on constitutional reform. He had served from time to time as Senior Adviser in the Ministry of Foreign Affairs; Science and Technology; Tourism; and Justice. Currently, he functions as the Chairman of the Board of Management of the Informatics Institute of Technology and serves on the Board of Directors of LOLC Holdings PLC; the Governing Board of the Regional Centre for Strategic Studies. He is also a member of the Academic Affairs Board for Post Graduate Studies of the Sri Lanka Institute of Development Administration (S.L.I.D.A); the Board of Management of the SANASA Campus; a Director of the Mercantile Merchant Bank/ Pathfinder Group and a member of the Board of Governors of Vidyodaya Pirivena - Maligakanda. Desamanya Pieris also lectures from time to time on invitation, at S.L.I.D.A.; the Defence Services Command and Staff College at Sapugaskanda; the Bandaranaike International Diplomatic Training Institute and the Kotelawala Defence University and at senior level training courses at various institutions.
He has delivered four convocation addresses, at the University of Colombo; Sri Jayawardenapura; Ruhuna and the Open University. He has, also on invitation delivered four National Memorial Orations the Lalith Athulathmudali Memorial Oration; the Sir Ponnambalam Arunachalam Memorial Oration: the Vidyajothi Professor V. K. Samaranayake Memorial Oration; and the Senator Dr. A. M. A. Azeez Memorial Oration, He has also been conferred the high National Honour of “Desamanya” for “Distinguished Service of a highly meritorious nature to the Nation”. He has written the foreword to several books authored by distinguished professionals in various fields and contributed articles to several commemoration publications including the 50th Anniversary commemoration volume of the University of Peradeniya and the Prime Minister Sirimavo Bandaranaike commemoration volume. He has recently written the Foreword to a limited edition Coffee Table Book entitled “A Pictorial Biography” of the world’s first woman Prime Minister, Sirimavo Bandaranayaike; and currently serves on a Presidential Committee to set up an international level “School of Public Policy and Governance”. He has published his memoirs of his experience in the public service of Sri Lanka in a book titled “In the pursuit of governance”.
