Kabbah was an international civil servant for almost two decades. After serving as deputy Chief of the West Africa Division of the UN Development Programme (UNDP) in New York City, he was reassigned in 1973 to head the Programme's operation in the Kingdom of Lesotho, as Resident Representative. He also headed UNDP operations in Tanzania and Uganda, and just before Zimbabwe's independence, he was temporarily assigned to that country to help lay the groundwork for cooperation with the United Nations system.