[1] Du Plessis was born on 25 June 1900 at Philipstown and received his education at Steynsburg, Petrusville and later at the Wynberg Boys' High School in Cape Town.

It was in these years that his interest arose in the social life and cultural products of the Malays.

In the thirties he travelled much abroad, including Europe, East and South America.

In 1948, he became head of the Institute of Malay Studies at the Cape Town University and from 1953 to 1963 he served as commissioner and later secretary and adviser for Coloured Affairs, a position that enabled him to advocate a particular vision for people the state labelled as Cape Malay.

[3] He also advocated for the establishment of the University of the Western Cape for so-called Coloured students, and he was the first Chancellor.