Maphai will take up the Johannesburg-based position at the start of May and will report to BHP Billiton executive director Mike Salamon.
The company said the new role reflected its commitment to the region and to playing a constructive role in the development of the countries in which it has an operating presence.
Maphai has an MA (Magna cum laude) from the University of Leuven in Belgium, a Doctorate of Philosophy from the University of Natal in South Africa and has also completed the Advanced Management Programme (AMP) at Harvard. He is currently Corporate Affairs Director at SAB Miller based in Johannesburg.