He listed his calling as a Rancher and had three years previous militia service in Cobourg, Ontario.
He was an original who attested with the 9th Battalion at Valcatier on 22 September 1914 at 22 years of age. He was 5′ 7 1/2″ with a dark complexion, blue eyes and brown hair. He sailed from Quebec to England aboard the SS Zeeland with the 1st Division in October 1914.
On 26 April 1915 he was wounded near Ypres in the left foot which resulted in fractured “small bones” and being in a cast for 10 days. He contracted influenza in July 1915.
He was admitted to the hospital in September 1916 with a shell wound of the left foot and ankle. He suffered a fractured left ankle in late May 1916 and was discharged a month later. He spent time recovering in England and was transferred from command to command in mid-1916 to mid-1917 in England.
He was killed at 26 years of age while in service with the 3rd Battalion, Canadian Expeditionary Force on 8 August 1918 during the Battle of Amiens, while on duty as a Battalion runner, during operations near Marcelcave, was hit in the heart and instantly killed by an enemy rifle bullet.
McArthur is buried at Toronto Cemetery, Demuin, Somme, France.