Leibbrandt was born on 25 January 1913 in
Potchefstroom, in the
Transvaal, the third of six children of Meyder (Meider) Johannes Leibbrandt. His father was of German descent, and his mother was Irish. Leibbrandt's father had fought with the Afrikaner forces in the
Second Boer War, and was subsequently a Sergeant-Major in the
South African Army, but in 1914 on the outbreak of
World War I, he had objected to an order to invade
German South-West Africa in a military campaign against the imperial German forces there, stating that it was his belief that "Germans should not war against Germans". In the late 1920s, Robey Leibbrandt established himself as an accomplished
pugilist. Leibbrandt represented South Africa at the
1934 Empire Games and won the light heavyweight bronze medal. He also represented South Africa at the
Berlin Olympics in 1936, competing in the
light heavyweight class. He was not able to fight the bronze medal bout with
Francisco Risiglione and finished fourth. He became South African heavyweight champion on 31 July 1937 in Johannesburg, beating
Jim Pentz. ==German military service==