He served with the 1st Battalion of his regiment in South Africa during the Second Boer War. The battalion was present at the operations around Colesberg in January 1900, following which he was promoted to lieutenant on 29 January 1900; then took part in the battle of Paardeberg (February 1900) and the subsequent march to Bloemfontein, during which he was aide-de-camp (ADC) to Brigadier General Theodore Stephenson. His battalion joined the force that subsequently went to occupy Pretoria, and took part in the engagement at the Vet River, and the battles of Diamond Hill (June 1900) and Belfast (August 1900).[4][5]
For his service in the war, he was awarded the Distinguished Service Order (DSO) in the October 1902 South African honours list.[6]
After the war ended in June 1902, Howard stayed in South Africa as ADC to Stephenson, who was now Major-General in Command at Bloemfontein district.[4][7]
Major-General T. H. Shoubridge (centre, front), GOC 7th Division, and his staff, standing on the steps of his headquarters, Italy, 1918. To his right is his GSO1, Lieutenant Colonel G. W. Howard.
He was promoted to brevet colonel in June 1919[10] and was appointed deputy director for organisation at the War Office in 1921, general staff officer at Aldershot Command in 1924, and commander of the 9th Infantry Brigade in 1927.[3] After receiving a promotion to major general in March 1931,[11] he went on to be major general in charge of administration at Eastern Command in June 1931[12] and in March 1934 became general officer commanding of the 5th Division,[13] which he led in Egypt, Palestine and Transjordan during the Arab revolt in 1934 before retiring from the army in 1938.[3] He had been promoted to lieutenant general in February 1937.[14]