Born at Luddington in 1885, Willie was the second son and one of the six children of Thomas and Mary Ann Millar (nee Pattrington). His mother was from Starbotton (or Buckden), North Yorkshire, and his father was from Glasgow. In 1901 the family lived in the High Street and his father worked as a domestic gardener. Willie was still living at home in 1911 and worked locally as a farm labourer.
According to his army number Willie enlisted as a territorial soldier with the King’s Own Light Infantry (KOYLI) at Goole in mid 1915. He would have done his initial service with the 2/5th Battalion as the 1/5th Battalion had gone out to France in April 1915. Willie may not have arrived to France until the 2/5th KOYLI did in January 1917 although it is possible he may have gone out as a reinforcement for the 1/5th KOYLI in 1916?
In 1918 the two KOYLI battalions had been amalgamated into one 5th Battalion. In July 1918 this combined regiment was serving with 187th Brigade in 62nd (2nd West Riding) Division when they moved to the Marne to reinforce the French Army against a German attack on Rheims.
On 20th July the Division began a counter-attack, now known as the Battle of the Tardenois, on the German positions around Courmas. The objective of the 5th KOYLI was to clear the western edge of the heavily wooded Bois du Petit Champ, around Courmas. The attack progressed well until it reached the woods around the Château de Commetreuil, west of Courmas where they came under machine-gun fire, suffering very heavy casualties.
Wounded in the attack at the Château de Commetreuil, Willie was taken to a field hospital at Ecueil. Here three days later William Millar died of his wounds.
Originally buried in Ecueil Farm French Military Cemetery, following the armistice his body was exhumed and he is now buried in Marfaux British Cemetery.