He began his military career in the Transvaal republican forces in Pretoria on the 21st February 1896, and fought in the Anglo-Boer War (1899-1902).

He returned to military service in World War I, and commanded a Union Defence Forces formation in the German South West Africa Campaign (1914-1915). In the German East Africa Campaign (1916-1918), he commanded a South African Overseas Expeditionary Force mounted brigade, then a division, and finally (1917-1918) all the British imperial forces in the region (though, allegedly, he could hardly speak English). He was knighted twice for his services.

After the war, he was a part-time inspecting officer. He was made a Grand Officer of the Portuguese Military Order of Aviz in 1921. In 1922, he commanded a mounted brigade in operations to crush the Rand Revolt on the Witwatersrand. He died later that year.

References

• Van Deventer W.D Dr (1993) Van Deventer stamboom en Agtergrond
• Nothling, C.J. (1994). Suid-Afrika in die Eerste Wereldoorlog.