When the South African War (1899-1902) broke out Gerhardus Gravett fought for the Boers, first as a Veld Cornet, then later as a Commandant and finally as Combat General in overall charge of the Boksburg Commando.
He saw action in Natal, the Free State, the Cape Colony and finally in the Western Transvaal.
On about 12 October 1900, Gerhardus Gravett was wounded while on commando near Roosenekal.
His comrades brought a Dr Neethling to attend to him but without medicines the doctor could not do much, and he contracted bronchitis.
He died on 26 October 1900, aged 42.
