Born in Chorlton on Medlock, Manchester on 8 March 1892 to a Church of England clergyman, by 1901 he was living with his family in Nelson, Lancashire.
On his 18th Birthday on the 8 March 1910 he joined the Royal Navy and was stationed on the Fisgard as a ‘Boy Artificer’, a Mechanical Training Establishment. He was discharged on 1 July 1911.
He emigrated to Canada when he was 20, arriving on 9 June 1912. His occupation was noted as a clerk but on he said he would be entering employment as an Engineer on his passenger records. While living in Canada he became a member of the Orange Order.
Three days after the start of the First World War he joined the 19th Lincoln Regiment in Ontario, Canada, before completing his officer training and eventually joining the 102nd Battalion of the Canadian Expeditionary Force. In September 1918, at Boulon Wood, Lieutenant Lyall was to win the Victoria Cross for leading his men in the capture of 185 soldiers, 26 machine guns and one field gun over the two days of fighting. His achievements show that he was clearly a very talented soldier and also a great leader of men. Below is the citation for his award that was in the London Gazette on 13 December 1918:
Lt. Graham Thomson Lyall, 102nd Bn., 2nd Central Ontario R.
‘For most conspicuous bravery and skilful leading during the operations north of Cambrai. On September 27th, 1918, whilst leading his platoon against Bourlon Wood, he rendered invaluable support to the leading. company, which was held up by a strong point, which he captured, by a flank movement, together with thirteen prisoners, one field gun and four machine guns. Later, his platoon, now much weakened by casualties, was held up by machine guns at the southern end of Bourlon Wood. Collecting any men available, he led them towards the strong point, and springing forward alone, rushed the position single-handed and killed the officer in charge, subsequently capturing at this point forty-five prisoners and five machine guns. Having made good his final objective, with a further capture of forty-seven prisoners, he consolidated his position and thus protected the remainder of the company. On October 1st, in the neighbourhood of Blecourt, when in command of a weak company, by skilful dispositions he captured a strongly defended position, which yielded eighty prisoners and seventeen machine guns. During two days of operations Lt. Lyall captured in -all 3 officers, 182 other ranks, 26 machine guns and one field gun, exclusive of heavy casualties inflicted. He showed throughout the utmost valour and high powers of command.’
After the First World War, he settled in Scotland, joining the Territorial Army and becoming a Major commanding the 3rd AA Division Workshop Company, Royal Ordnance Corps. By the time of the Second World War he was a Colonal on the General Staff in Egypt, where he sadly died of heart failure on 28 November 1941.
The London Gazette, 13 December 1918