Duncan Mollison came from a footballing family, playing alongside brothers Alexander and David in Toowoomba.
Mollison enlisted in 1916, but unlike Alexander, who also enlisted, he would not survive the war. He was wounded in action twice in 1917, firstly in France and later in Belgium and was evacuated to England in both cases. Mollison rejoined the 26th Battalion in March 1916, but was killed in action in July.
His name was added to the Toowoomba British Association honour board alongside that of his brother Alexander. The association also remembered Mollison by name at the banquet for the visiting English team in 1925. Mollison had played for Cities before the war and was a Toowoomba representative player.