Mtonga, a medical doctor, is co-president of International Physicians for the Prevention of Nuclear War and is a member of the international steering group of the International Campaign to Abolish Nuclear Weapons. He cofounded the Zambia Campaign to Ban Landmines, is a member of the governance boards of the International Campaign to Ban Landmines and the Cluster Munition Coalition, and advises numerous international organizations on both landmines and small arms. He has collaborated with the World Health Organization's initiatives on injury prevention and on the global burden of disease and violence. He speaks and writes widely on development, violence, and war prevention from a public health perspective. He completed his medical studies at the University of Zambia in 1994.