The Regiment's original purpose was home defence, to supplement the British Army garrison which was stationed in Cape Town.

From February to August 1897, the Dukes were on active service in Bechuanaland, as part of a government military operation to capture dissident Tswana leaders who had taken refuge in the Langberg mountains.

In May 1900, it was assigned to Lt Gen Sir Charles Warren's column, to recapture areas of Griqualand West from Boer and Cape Rebel forces.

The Dukes' commanding officer, Lt Col William Spence, was killed in action during a Boer attack on the column's base on the farm Fabers Puts on 30 May 1900.

A second battalion was formed in Cape Town in January 1901, and in October 1901 it became a separate unit and was renamed the Colonial Light Horse.

Like other CF units, the Dukes played a limited role in World War I, because the South African forces were restricted to operations in southern Africa.

The Regiment was on garrison duty in Cape Town from October 1914 to January 1915, and was deployed in German South West Africa (now Namibia) from February to July 1915.

After the Dukes returned from GSWA, more than a hundred members volunteered for service in the new 1st SA Infantry Regiment, which served in Egypt and then on the Western Front in France.

The Dukes were converted into a counter-insurgency (COIN) unit in 1974, and served several tours of duty in the Border War, i.e. South African operations against the People's Liberation Army of Namibia.

The Dukes were deployed on internal security duties in various part of South Africa in 1985, 1986, 1988, and 1990, during the 1985-1990 State of Emergency, which was the government's response to the armed liberation struggle by the African National Congress and others.