The province of Africa was governed as any other senatorial province would be. Senators were chosen to serve one year terms as proconsuls and propraetors, taking the responsibility of governing and taxing the province, with the emperor selecting a procurator to report to him on the affairs of the province.
Africa was deemed a frontier province, and as such, normally would have a legion under imperial rule stationed to maintain control and keep out foreign invaders. The Third Augustan Legion, formed in 27 BC, was the exception to this rule, with its command being given to the senate.
The Third Augustan Legion patrolled the immense area of Africa, and for four hundred years was the only permanently garrisoned military force in Africa. Aside from quelling the occasional tribal revolts, there was not much for the legion to do. They ended up working on many of the roads in Africa, and settling quite a few townships wherever they stayed while traveling. The legion’s longevity without conflict is impressive, when compared to a province such as tiny Britain, which had four legions stationed in it during almost the whole Roman period.
For their armies in other provinces, the Romans recruited the famed and formidable Numidian cavalry. By the second half of the first century after Christ, the Third Augustan Legion was raising local recruits for service in Africa when needed.
The Romans had little fear of the native Africans or the settlers therein. Many had settled to sedentary lifestyles in or around the townships, and the prosperous lifestyle of the province left few naysayers to the Roman way.