In November 1918, Wallace was involved in an action in which he was recognized with the following citation:

"For conspicuous gallantry and devotion to duty, on 1st November, 1918, during the attack on Valenciennes, seeing a number of the enemy running into a large factory, he followed them in singlehanded and found them establishing machine gun posts. With great daring he rushed the party, killing and capturing all the crews with their guns. He personally reconnoitered the streets in front, under very severe machine-gun fire, killing two snipers and capturing a machine gun." For his bravery, he was awarded the DCM.

Wallace McMullan was born in Belfast, County Down, Ireland in 1884, the youngest of seven children born to John and Elizabeth (nee Wallace) McMullan. He moved to Canada where he graduated as a Mechanical Engineer and had his own machine shop in New Westminster, B.C. prior to joining the 47th Canadian Expeditionary Force in 1915.

He served four years fighting in France and Belgium where he won the Distinguished Conduct Medal (DCM) for bravery in the field of battle. In one daring feat, he captured over 140 enemy soldiers single handed in "Quarry Woods" in Northern France on Sept 18, 1918.

While patrolling near some woods, Wallace saw some movement in a rock quarry, which he knew to be the enemy. How many? He had no idea. He called them out, and one by one they emerged with their hands up. They were all dressed in private's greatcoats, and they ranged in age from teens to men in their sixties.

He recognized that some were officers, who he separated from the other ranks. He knew from their mannerisms, their rings, watches, and when opening their greatcoats, their pistols.

He was in the process of taking these items when an officer from the PPCLI attached to their regiment arrived on the scene, Lt Bill Gibson, from Calgary. Wallace was standing there with his rifle and over one hundred German soldiers in front of him with their hands up... and, convinced the Germans must have had a supply of liquor, Lt Gibson's first question to Wallace was, "Where's the Schnapps?".

Forty years later, after a chance meeting at the Officers Mess in White Rock B.C. and for the first time since the war, the two old warriors were able to share this story together again. And as before, Wallace's answer was the same, "there wasn't any".

His medals include the DCM, MM, Mons Star, War Medal and the Victory Medal. Sgt McMullan was also Mentioned in Dispatches. He also received two gold bars worn on the left sleeve, above the wrist for severe shrapnel wounds received in battle. He was demobilized in Aug 1919.

Wallace married Pearl Gertrude Davis in Winnipeg in 1920. They had four children, one daughter and three sons, all three of whom served on active duty during the Second World War.

Wallace was presented to King George and Queen Mary on their official visit to Winnipeg, MB in 1939. Sgt McMullan was buried in the "Field of Honour" in Vancouver, B.C. with a Guard of Honour from the Royal Canadian Legion.