Ernest de Brath was born on 12 Dec 1858, at Forest Hill, London. He was the son of Félix Dupeiron de Brath and Anna Louisa Mary Gertrude Monica née Higgs. His father, Félix, had been an artillery officer in the Spanish Army and been awarded the Cruz Laureada de San Fernando, the highest military award for gallantry. Ernest joined the British army as an officer in the 3rd Regiment of Foot (Buffs) on 11 Sep 1876 and transferred to the Indian Army in 1879, serving as a lieutenant in the 32nd (Punjab) Bengal Native Infantry (Pioneers).
His active service was in the 2nd Afghan War of 1878–80 and Waziristan in 1881. He was promoted to captain on 11 Sep 1887 and graduated at the Staff College in 1889. He was with the regiment in Hazara 1891 and the Dongola Expedition in 1897. He also worked on the staff of the Civil War Office, also known as the Military Department of the Government of India. For several years he was Assistant and Deputy-Secretary. He devoted himself to the work of reducing the Indian Army Regulations from 28 volumes of 6,000 pages to 13 complicated volumes of 1,000 pages. The complication was due to the unification of the Indian Army, from three Presidential armies and the Punjab Frontier Force. It was regarded as an astonishing achievement.
By 1904 he was a major-general and had succeeded Sir Edmund Barrow as Secretary to Government in the Military Department. In 1906 Lord Kitchener became Secretary of State for War, and Commander-in-Chief, and de Brath was appointed to the dual post of General Officer Commanding at Aden, and Political Resident. He held this post until 1910. He was appointed Companion to the Order of the Indian Empire (CIE) in 1903, Companion to the Order of the Bath (CB) in 1905. He was promoted to Lieutenant-General in 1910 and elevated to Knight Commander of the Order of the Bath (KCB) on 22 June 1914.
He was married to Edith Anna Beatrice O’Meara and they had two daughters and two sons, one of whom, Neville Stanley de Brath, was also an officer in the 32nd Sikh Pioneers. Ernest de Brath died in Nice on 12 December 1933.