Aged 19 on the outbreak of the Second World War, Jamieson was considered too young for overseas service and did not initially go with the battalion, now part of the 51st Infantry Division, to join the British Expeditionary Force when it went to France in 1940 but followed later. When the majority of the battalion was captured in June 1940 during the Fall of France he was at Rouen and was able to return to Britain. The battalion was reformed in 1941 and he was promoted to a company commander of D Company.
Victoria Cross
Jamieson was a 23-year-old captain in the 7th Battalion of the Royal Norfolk Regiment, now part of the 176th Infantry Brigade attached to the 59th Infantry Division, when the following deed took place for which he was awarded the Victoria Cross. On 7/8 August 1944, south of Grimbosq, Normandy, France, Jamieson was in command of D Company, being the only officer remaining, which had established a bridgehead over the River Orne. The enemy made seven counter-attacks on the company's position, but throughout 36 hours of bitter and close fighting Captain Jamieson's company refused to give up. The attacks included assaults with Tiger and Panther tanks which shot up the Royal Norfolks' tanks. Jamieson at one point mounted a British tank to talk to the commander under enemy fire. He dismissed it as anything heroic, saying that he had to as the telephone didn't work – tanks were equipped with an external handset so that the commander could talk to an infantry commander without opening the hatch. The image of Captain Jamieson riding a Churchill tank while enemy tanks attacked was immortalised in a painting. The citation for Captain David Jamieson in the London Gazette of 26 October 1944 ends:
Post-war
Following the war, he worked for the Australian Agricultural Company, which ran several sheep and cattle stations; he became a director in 1949 and was Governor from 1951–75. He was also director of other companies including National Westminster Bank. Due to his height, 6 ft 5, he was designated the ceremonial umbrella man to Queen Elizabeth, the Queen Mother, carrying an umbrella over her at social functions. In 1948 he married Nancy Elwes, who died in a car accident in 1963. He remarried, to Joanna Windsor-Clive, in 1969. He was appointed High Sheriff of Norfolk in 1979. He died on 5 May 2001 in Burnham Market, Norfolk, and was interred in the churchyard in Burnham Norton. He was survived by his widow, his son Andrew Jamieson, and two daughters of his first marriage, three grandchildren, and by a stepson and stepdaughter.