Parris was educated at Queen’s College, Georgetown, where he won the Guiana Scholarship in 1959. He attended the University of the West Indies, Mona, Jamaica, earning the BSc (Mathematics), 1962 and the London School of Economics, earning the BSc (Economics), 1966 and the MSc (Economics), 1967.
He served as Chief Economist, Bank of Guyana and Head of the State Planning Secretariat. He was also appointed Chief Executive Officer of the Guyana Bauxite Company and later, Minister of Planning and Development and Deputy Prime Minister. He was a member of the Guyana Elections Commission and the Constitution Reform Commission.
William Haslyn Parris was awarded the Cacique’s Crown of Honour (CCH) for his public service
