Born in Northern Ireland, he was initially called Stuart Christopher H. McIlwrath, but took his mother's maiden name after his parents separated.
[1] As a student and collaborator of Neville Chittick, he worked on the 1973-74 excavation project of the British Institute in Eastern Africa (BIEA) in Aksum, the capital of the late-antique Aksumite Empire.
The excavations had to be cancelled due to the Derg's coup d'état in 1974, but Munro-Hay continued to dedicate his work to researching the history of Aksum, and in particular compiled a large collection of Aksumite coins.
He completed his doctorate in 1978 at the London School of Oriental and African Studies (SOAS), supervised by the then BIEA chairman Laurence Kirwan, his thesis was titled A Reappraisal of the History and Development of the Aksumite State from Numismatic and Archaeological Evidence.
He was then employed by the British Institute in Eastern Africa, on whose behalf he published the results of the excavations in Aksum.