Johnson is an Assistant Chief Statistician and the Acting Director for the Communication and Dissemination Directorate (CDD). He also heads the Resource and Data Centre (RDC) of the Service and currently leads the 2020 Population and Housing Census Technical Working Team.
Johnson is a Labour Statistician and holds a Master of Arts Degree in Economic Policy Management and a Bachelor of Arts degree in Statistics and Economics, both from the University of Ghana. He has worked for the Ghana Statistical Service since 1997 and has participated in a number of national censuses, surveys and other research activities. Kagya has contributed to over 20 publications and innumerable training programmes by the Service. He wields a lot of experience in both quantitative and qualitative research work. Prior to his engagement by the Ghana Statistical Service, he taught Mathematics and Statistics at Ghana National College, Cape Coast. His interests include teaching as well as designing, implementing, monitoring and evaluation of research programmes.