They were the first winner of the Allan Cup in 1909 when the cup was given to the winner of the Inter-Provincial Hockey League. Alf Smith coached the Ottawa Cliffsides to win the first Allan Cup in March 1909, only to lose it to Queen's University in a challenge.
The Cliffsides played for only three seasons in the Inter-Provincial league. They then reappeared in the Ottawa City Senior League in 1919–20 before disappearing for good.