He was trained in Laboratory Technology at the Government Technical Institute Guyana, Guyana Mining Enterprise and University of Guyana. He was a quality control technician for two years and worked as Supervisor for the Research and Development Laboratory at Guyana Mining Enterprise for approximately ten years, and spent two years in the Mahaica Mahaicony Abary Agricultural Development Authority in Guyana, as a senior lab technician, responsible for Environmental Monitoring And Control, The Management of Soil, and the Monitoring of the Quality of Irrigation Water within the project area. Mr. Gillis also functioned as senior lab technician for over 18 years at the Antigua State College, where he was responsible for preparing all Chemistry practicals and managing the Science Block.