He was born of Nicolaas Frans Prinsloo (1813 - 1890) and Isabella Johanna Petronella Rautenbach (1819-around 1908) in the district of Graaff-Reinet, South Africa who migrated to the Orange Free State where they lived in Bloemfontein, Waterval and Bethlehem.

[5] In 1876 Prinsloo was elected a Member of the Volksraad (House of Assembly) of the Orange Free State in Bloemfontein for Koranaberg and served on several committees, establishing a reputation as an eloquent speaker.

Prinsloo and general Schalk Burger were later criticised for their lack of direction when the Boers attacked the strongholds of Caesar's Camp and Wagon Hill at Platrand massif just south of Ladysmith on January 6, 1900.

[3][4] Prinsloo and his men guarded the mountain passes of the Drakensberg while generals Christiaan de Wet, Paul Roux and Jonathan Crowther would each retreat with their troops northwards and eastwards.

Christiaan de Wet called it a “a horrible murder of government, country and people” (Afrikaans: ’n gruwelike moord op regering, land en volk).