A soldier with The Royal Scots during the First World War, he was posthumously awarded the VC for his actions on 22 October 1918, during the Hundred Days Offensive.

[3] The citation for McGregor's VC read: "For most conspicuous bravery and devotion to duty near Hoogemolen on 22nd of October, 1918, when in command of a section of machineguns attached to the right flank platoon of the attacking battalion.

The driver, horses, and limber were all hit but Lt. McGregor succeeded in getting the guns into action, effectively engaging the enemy, and enabling the advance to be resumed.

With the utmost gallantry he continued to expose himself in order to direct and control the fire of his guns until, about an hour later, he was killed.

"McGregor's body was recovered and he is buried in the Stasegem Communal Cemetery in West Flanders, four kilometres to the east of Kortrijk.