In 1971 he became the commander of the Police Mobile Unit, becoming the first citizen to occupy such a position. When Botswana formed the Botswana Defense Force (BDF) in 1977, Merafhe was selected by President Sir Seretse Khama as its first commander at the rank of Major-General.
Merafhe assumed leadership of the Police Mobile Unit in 1971, marking a historic milestone as the first non-official to hold such a role. Subsequently, when Botswana created the BDF in 1977, Merafhe was appointed by President Sir Seretse Khama as its inaugural commander at the rank of Major-General.