Major Harry Schmidt of the Illinois Air National Guard had blamed the bombing on the "fog of war," saying he mistook the Canadians' gunfire for an attack from Taliban fighters.
The 38-year-old pilot said his superiors never told him that the Canadians would be conducting live-fire exercises near Kandahar airport that night.
Schmidt originally was charged with manslaughter and aggravated assault, but the charges were reduced last year to dereliction of duty. He was found guilty after a closed hearing last week in what the military called a "non-judicial forum."
Schmidt is from the central Illinois town of Sherman, near Springfield.