Donald Seth-Smith first came to British East Africa in 1904 as a young Oxford undergraduate to visit his older brother Martin, who had come to Kenya a year earlier. In 1908 Donald bought a farm near Thika together with Lord Cranworth, Alan and Roland Thompson and Mervyn Ridley. Donald worked hard developing the farm, which today is called Kakuzi Ltd. Donald and his brother Martin enjoyed hunting safaris and both were excellent sportsmen. When the First World War broke out in 1914, Donald joined the Supply Corps and later enlisted in Logan's Battery for the push into German East Africa. Donald received the Military Cross in January 1917 for bravery in the battle for Kibata in southern Tanganyika. Donald's diary records his war experiences from January 1916 in Tsavo until he was invalided back to Kenya in February 1917.