[1][2][3] Jan Celliers was born in Fraserburg in the Karoo, Northern Cape, as a son of Jacob Daniel Celliers (circa 1835 - 1871) and Johanna Elizabeth Blom (Kruger, Fraserburg, circa februari 1837 - Lichtenburg, 11 July 1921).

At a young age Celliers migrated to the Transvaal (South African Republic) where he fought in the First Boer War (1880-1881) in the Marico Kommando.

He became renowned for his methods of firing a gun while galloping fast on a horse,[4] as well as silencing British cannons.

[3][5] In early 1902 he surprised with less than 500 soldiers British Colonel Stanley Brenton von Donop and his 1000 troops who fled.

[6] In a meeting with Boer commanders on 29 May 1902 at Vereeniging, Celliers' vote was with those who proposed to stop fighting.