Cannon was born on April 6, 1839 at Bridgeville, Delaware. His father, William Cannon, was a successful merchant who later became governor of Delaware during the war.  At Dickinson, Cannon was a member of the Union Philosophical Society as well as Phi Kappa Sigma.  He received his bachelor of arts degree in 1860.  After graduation he obtained a position at the Census Bureau in Washington, D.C. 

Cannon became a captain of the 1st Delaware cavalry in the Army of the Potomac and was placed in command of Company B of that unit.  He contracted typhoid fever during the occupation of Bel Air, Maryland, dying there on August 18, 1863.