[1] In 1963 he registered for a degree in English at the University of Natal,[2] but switched courses to History under the influence of Colin Webb.
His Ph.D. thesis was later published as The Destruction of the Zulu Kingdom: The Civil War in Zululand, 1879-1884[3] After graduating with the Ph.D. degree, Guy taught for a while in London, but later moved to Lesotho where he lectured history at the Roma campus of what was then the University of Botswana, Lesotho and Swaziland.
In 1992 he returned to South Africa and became head of the history department at the Durban campus of the University of Natal.
[2] While studying for his doctoral degree in London he met and married Naimi Haque.
[2] Guy died at Heathrow Airport while travelling back home to South Africa after attending a conference and giving a lecture marking the bicentenary of the birth of John Colenso, the first bishop of Natal.