On 1 February 1915, during the First World War, and while serving with the British Army, near Cuinchy, France, Lance Corporal O’Leary was part of a storming party that rushed the opposing front.
They captured two enemy positions and prevented the enemy from firing on advancing troops and allowed them to gain considerable ground.
For this action he was awarded the Victoria Cross.
O’Leary emigrated from Ireland, and at the outbreak of the war, was a member of the Royal North West Mounted Police, posted to Battleford and later Regina.
When forming one of the storming party which advanced against the enemy’s barricades he rushed to the front and himself killed five Germans who were holding the first barricade, after which he attacked a second barricade, about 60 yards further on, which he captured, after killing three of the enemy and making prisoners of two more. Lance-Corporal O’Leary thus practically captured the enemy’s position by himself and prevented the attacking party from being fired upon.
Victoria Cross citation in The London Gazette, February 16, 1915