After transferring to the 2nd Gurkha Rifles in the Indian Army, he saw active service on the North West Frontier, but after learning to fly in 1911 turned towards a career in military aviation.

During the First World War he rose from flying instructor to command of 41st Wing RFC, the main strategic bombing force, and was awarded the Albert Medal for putting out a fire in an explosives store.

[12] On taking command of the squadron, he chose to stop flying personally in order to concentrate on administration, a decision which was regarded dismissively by his men; relations were strained until January 1916, when he demonstrated his courage by walking into a burning bomb store to try to control a fire.

He was awarded the Albert Medal for this act on the personal recommendation of General Hugh Trenchard, and in February 1916 was promoted to lieutenant colonel and given command of Training No.

[8] He was appointed to a League of Nations disarmament committee in December 1925[8] and then became Deputy Chief of the Air Staff and Director of Operations and Intelligence on 12 April 1926.

[20] He was appointed a Companion of the Order of the Bath in the 1929 Birthday Honours[21] and, having been promoted to air vice marshal on 1 January 1930,[22] he stood down as Deputy Chief on 6 February 1931.

In this, he was a supporter of the standard doctrine of the day, which suggested that the destructive power of a bomber force was sufficiently great that it could cripple an industrial economy in short order, and that so merely its presence could potentially serve as an effective deterrent.

[29] On 1 September 1937, Newall was appointed as Chief of the Air Staff, the military head of the RAF, in succession to Sir Edward Ellington.

[1] The most prominent candidate was Hugh Dowding, the head of RAF Fighter Command and senior in rank to Newall by three months, who had been informally told by Ellington in 1936 that he was expected to be appointed as the new Chief of the Air Staff.

[1] While he remained committed to the idea of a "knock-out blow" offensive by Bomber Command, he also recognised that it was too weak to do so successfully, but still strongly opposed the use of the RAF for close air support.

[1] Following the end of the Battle of Britain, Newall was quickly forced into retirement and replaced as Chief of the Air Staff by Charles Portal.

Contemporaries attributed this to the effects of overwork, which had certainly taken its toll,[1] but there were also other aspects; Newall had lost political support, particularly following a dispute with Lord Beaverbrook over the control of aircraft production and repair.

[36] Matters came to a head with the circulation of an anonymous memo attacking Newall, among other senior officers, as "a real weakness to the RAF and to the nation's defences".

[42] Newall and his wife, who also carried out an extensive program of engagements, were broadly popular, but there were occasional tensions; shortly after his arrival, it was widely (but mistakenly) rumoured that he had slighted the "men" of the Army in favour of the "gentlemen" of the RNZAF in a speech.

[43] Politically, he had a lukewarm relationship with the Prime Minister, Peter Fraser – "I can't persuade myself that he is all he quite appears to be",[44] Newall noted in a private report – but the two worked together effectively.

Fraser, and his deputy Walter Nash, refused to accept this response, and the impasse stretched out for several days; in the end, a compromise was reached where Newall remitted the sentences but the government undertook to repeal the legislation.

[46] A second conflict emerged just before the end of his term, when in 1945, the Labour government sought to abolish the country quota, a system that gave additional electoral seats in rural areas.

Farming groups – predominantly National-supporting – strongly opposed the move, and argued that such a major change could only be made after gaining approval in a general election.