Like many Creoles, Porter was of West Indian, Jamaican Maroon, Liberated African, and Nova Scotian settler descent.

His paternal grandfather was Arthur Thomas Porter I (1834–1908), a successful Creole businessman of West Indian and Jamaican Maroon parentage.

The Virginian had occupied a house in what the Nova Scotians called Settler Town, Sierra Leone, and was one of the founders of Freetown.

Porter was educated at the Freetown Secondary School for Girls before proceeding to Fourah Bay College and obtaining his bachelor's degree.

He subsequently obtained a bachelor's degree in history from Selwyn College, Cambridge, before earning his doctorate in sociology at Boston University.