Jacobus Francois Marais, son of Francois Paulus Marais and his wife Johanna Geertruida Marais, matriculated through the University of the Cape of Good Hope (an examining university) in 1885 and was awarded the degree Bachelor of Arts (BA) by the same institution in 1887. He graduated as Doctor of Science (DrSc) at some time before 1893, probably in Germany. From 14 June 1893 he was a temporary assistant in the Government Laboratory in Cape Town under C.F. Juritz* for some months. During that year he carried out analyses on imported fertilisers and reported the results in the Agricultural Journal of the Cape of Good Hope in September (Juritz, 1896). That same year he contributed to viticulture by compiling a booklet, The reconstitution of phylloxerised vineyards; with special reference to the American vine both as graft-bearer and direct producer. It was published by the Department of Lands, Mines and Agriculture in both English and Dutch editions (Cape Town, 1893, 66p). At some time between 30 September 1893 and 22 January 1894 he was appointed as assistant colonial bacteriologist of the Cape Colony, but does not appear to have held the appointment for long. During 1898-1900 he was an examiner in organic and agricultural chemistry for the University of the Cape of Good Hope.
Marais, using the pseudonym "M. Hugeno", entered the field of popular literature with a booklet, Arie Bloemeris (Cape Town, 1899, 64p), describing the "adventures of three South African students at medical schools in Edinburgh and Germany" (South African bibliography, 1979). A copy of the book in the Cory Library, Grahamstown, contains a pencilled note by the chemist B. de St.J. Van der Riet*, identifying the author as "my friend and fellow student Jacobus Francois Marais who was Rector of the Boys' High School, Stellenbosch, at the time of his tragic death at Rooi Els". [Van der Riet studied for his doctorate in chemistry at the Universities of Halle and Heidelberg between 1890 and 1893, and the two may have been fellow students during this period.]
Marais was married to Louisa Adriana Hofmeyer, with whom he had two daughters.