He was born to a middle-class family in Kingston, Jamaica. By 1951, he had won ten first prizes in West Indian literary competitions. His integral role in the development of political and cultural nationalism is evidenced in his being awarded the high honour of the Order of Jamaica in 1978.
Mais published more than a hundred short stories, most being found in Public Opinion and Focus. Other stories are collected in Face and Other Stories and And Most of All Man, published in the 1940s.Mais's play, George William Gordon, was also published in the 1940s, focusing on the Morant Bay Rebellion of 1865.
It played an important role in the rehabilitation of the eponymous character who was in conventional colonial history described as a rebel and traitor, but who would be proclaimed, on the centenary of the rebellion, a national hero.
His short stories were collected in a volume entitled Listen The Wind, thirty-two years after his death. Mais's novels have been republished posthumously several times, an indication of his continuing importance to Caribbean literary history. He also had an influence on younger writers of the pre-independence period, notably John Hearne. Many of Mais's manuscripts have been deposited in the library of the University of the West Indies, Jamaica.