Maurice was born in Dublin, the son of John Frederick Maurice, a British Army officer and military historian. He attended St. Paul's School and Sandhurst before joining the Derbyshire Regiment in 1892. His first overseas posting was to British India in 1897–98, during the Tirah Campaign. During this time, he served as aide-de-camp to his father, Major-General John Frederick Maurice. After a promotion to captain in 1899, Maurice fought with the Sherwood Foresters (Derbyshire Regiment) in the Second Boer War 1899–1901.
Before leaving for South Africa, he married Margaret Helen Marsh, the daughter of Frederick Howard Marsh, and the sister of Edward Marsh, at St George's, Hanover Square.
Maurice was promoted brevet major in November 1900. On returning from South Africa, he entered the Staff College in 1902. Later that year, he was posted to the War Office, and his daughter Joan was born in 1903.
Before 1911, Captain Maurice was promoted to major. Two years later, he was promoted to lieutenant colonel in 1913 and transferred to the Staff College as an instructor in military history at Camberley under Robertson, then Commandant.
On the outbreak of war in 1914, Maurice was posted to France and assigned to 3rd Infantry Division as a staff officer. He saw action at the Battle of Mons in August 1914. In early 1915 Maurice was posted to London as Director of Military Operations for the Imperial General Staff, and in 1916 he was promoted to major general.
Maurice worked closely with William Robertson, who was appointed Chief of the Imperial General Staff at the end of 1915, ghostwriting many papers which went out over Robertson's signature.
Following the dismissal of Robertson in February 1918, Maurice became convinced that troops were being withheld from the Western Front in order to undermine the position of Douglas Haig. When David Lloyd George announced in the House of Commons that British troop levels on the Western Front were at all-time highs, Maurice believed that he was deceiving both Parliament and the British public. In his capacity as Director of Military Operations, Maurice knew that the troop statistics available to his office did not bear out Lloyd George's claims, and he wrote to Robertson's successor, Henry Wilson, to outline his position. After Wilson failed to respond, Maurice wrote a letter to The Times, criticizing Lloyd George for misleading the public about the state of the British Expeditionary Force during the German Spring Offensive. The publication of this letter on 7 May caused a political storm, and members of the Liberal opposition, including former Prime Minister H. H. Asquith, called for a debate. This subsequently occurred on 9 May, and Lloyd George was able to imply that the source of confusion was, in fact, Maurice's office, rather than the Prime Minister's. Maurice was initially suspended, and ultimately forced to retire; he was also denied a court martial.
Following his forced resignation, Maurice served as a military correspondent, initially for the Daily Chronicle, and later for the Daily News. In 1919, the reviews in the German press that grossly misrepresented his book, The Last Four Months, contributed to the creation of the stab-in-the-back myth. "Ludendorff made use of the reviews to convince Hindenburg."
In a hearing before the Committee on Inquiry of the National Assembly on November 18, 1919, a year after the war's end, Hindenburg declared, "As an English general has very truly said, the German Army was 'stabbed in the back'."
In 1921, he was one of the founders of the British Legion, and although he was not initially very active in the organization, he would later serve as the president from 1932 to 1947. During the Munich Crisis, he volunteered the services of the Legion to the government. He flew to Berlin to meet Hitler for the formation of the short-lived British Legion Volunteer Police Force. The following year, he was appointed principal of the Working Men's College in London, a position he held until 1933, when he left to take a similar post at East London College. He was also appointed as a professor of military studies at the University of London in 1926, and taught both there and at Trinity College until the end of his life.
Maurice died on 19 May 1951, in Cambridge well cared for by his daughter, the economist Joan Robinson.
The Russo-Turkish War, 1877–1878 (Special Campaign Series, 1905)
Sir Frederick Maurice: a record of his work and opinions (Edward Arnold, London, 1913)
Forty Days in 1914 (Constable and Co, London, 1919)
The Last Four Months (Cassell and Co, London, 1919)
The Life of Lord Wolseley (William Heinemann, London, 1924)
Robert E. Lee, the soldier (Constable and Co, London, 1925)
Governments and War (William Heinemann, London, 1926)
An aide-de-camp of Lee (Little, Brown and Co, London, 1927)
The Life of General Lord Rawlinson of Trent (Cassell and Co, London, 1928)
British Strategy (Constable and Co, London, 1929)
The 16th Foot (Constable and Co, London, 1931)
The History of the Scots Guards (Chatto and Windus, London, 1934)
Haldane (Faber and Faber, London, 1937, 1939)
The Armistices of 1918 (Oxford University Press, London, 1943)
The Adventures of Edward Wogan (G Routledge and Sons, London, 1945)