He was a public defender of Upper Canada College, and was also known for virulent Anti-Americanism; after a proposal was made to erect a statue of George Washington in Westminster Abbey, he threatened that if it were built, he would go there to spit on it. Following the attempts by the Fenian raiders to "liberate" Canada between 1866 and 1871, Denison claimed a Yankee sword from the battlefield for a poker on his fire.