Between 2012 and 2016 he was a Programme Coordinator for the African Science Technology and Innovation Indicators Initiative of NEPAD. He was the first Regional Director for the NEPAD Southern African Network for Biosciences (SANBio) at the Council for Scientific and Industrial Research Centre (CSIR), in Pretoria, South Africa between 2006 and 2012. Prior to that, between 1995 - 2004 he served in the School of Natural Sciences at UNZA as Dean, Head of Department and as Assistant Dean.

Prof Mumba emerged as a Staff Development Fellow (SDF) in the Department of Biology in 1985 and progressively ascended to Lecturer, Senior Lecturer and to Associate Professorship in 2005.

Prof Mumba has contributed to the development of STI strategies and policies at national, regional and continental levels in Africa. He is currently a member of the African Union Commission (AUC) Monitoring and Evaluation (M&E) Committee on the “Science, Technology and Innovation Strategy for Africa” (STISA-2024).

He is the Founding Director of the Biotechnology Outreach Society of Zambia, a professional association spearheading biotech outreach in Zambia. He is also one of the founding trustees of the Zambian Academy of Sciences.

On 1 July 2016, he was appointed as the new Vice Chancellor of the University of Zambia.