Maurice was the fifth of the six children of Dr Thomas Greenhalgh and Elizabeth Greenhalgh. He was born on 29 May 1895 in the Heaton Norris area and later educated at Holm Legh, Buxton and St bees College.
His brothers and sisters were Thomas, born 1883, who in 1915 was living at "Lezaire", Chapel-en-le-Frith; Harold, born 1889, who had emigrated to Australia; Gertie, born 1881; Gladys, born 1890 and Doris, born 1897.
Maurice originally enlisted into the army at Westminster, joining the 19th Battalion, Royal Fusiliers (commonly known as the 2nd Public Schools Battalion). He joined up on 15 September 1914 and was given the service number of 3496. His enlistment papers show him to have been 5' 9" tall and he weighed 122pounds. He had a fair complexion, blue eyes and fair hair. His occupation was as an assistant to a cotton spinner. The Manchester City Battalions Book of Honour records Maurice as an employee of cotton doublers Isaac Pearson Ltd, Goyt Mills, Stockport.
As with many middle class recruits, Maurice was quickly singled out to become an officer and, by 29 October 1914, he had been discharged to a commission. He left for France on 17 August 1915 as a 2nd Lieutenant in the 15th Battalion but, whilst at 20 Infantry Base Depot, he was reassigned to the 6th Battalion. He joined his unit on 24 August. A month later he was dead.
On 25th September, the Battalion was in trenches near the Somme village of Curlu. Patrols were regularly sent out into No Man's Land which, in this sector, comprised marshes and woods along the river. At 2.30pm, Maurice took out a patrol of nine other men into the marshland. The direction they took is described by the Battalion's War Diary as via 1st Plantation, 2nd Wood, 2nd Plantation to 4th Wood. As they moved into the wood, the patrol was fired on from the centre. The men scattered and lay down. They did not reply vigorously to the enemy fire as the wood was in front and the dense undergrowth meant they could not see the Germans.
After about five minutes, the Germans started to advance and, at this point, the British opened heavy fire on them and the Germans gradually withdrew to their original positions. The King's now fell back to what is described in the official records as their "ambush", although there had been no previous mention of an ambush position being set up.
When they reached the "ambush point", they realised that Maurice, the scout sergeant, a lance corporal and a private were not with them. Shortly afterwards, re-enforcements under Lieutenant Blackledge arrived, having heard the firing. They pushed forward back into the wood, where they found Maurice, mortally wounded, and the sergeant and private dead. There was no sign of the lance corporal. Lieutenatnt Blackledge's party brought back the three bodies.
When Maurice's affairs were settled, his will had left £291 2s 7d.
Later, the Stockport Advertiser, in its edition of 12 November 1915, reported "At the monthly meeting of the Committee of Stockport Infirmary, the Chairman announced that the employees of Goyt Mill Company, Stockport, had subscribed to a memorial to M Greenhalgh who was recently killed in action. Lt Greenhalgh was the son of the late Dr Greenhalgh who was for many years honorary house surgeon of the Stockport Infirmary and on the suggestion of Mrs Greenhalgh - and with the hearty concurrence of the Committee - the memorial took the form of a clock in the operating theatre of the Infirmary."