James Ernest "Buck" Karnes was a Sergeant in the United States Army who received the Medal of Honor for his actions near Estrees, France, on October 8, 1918, during World War I. James Ernest "Buck" Karnes (July 20, 1889–July 8, 1966), was born in Arlington, Tennessee and grew up in Knoxville, Tennessee.

Karnes entered active duty with the United States Army's 117th Regiment from the Tennessee National Guard during World War I.

On October 8, 1918 Karnes' company was stopped near Estrées, France, by a German machine gun position.

Karnes and Private Calvin John Ward, deciding they had "had all they could take" of this situation, fixed bayonets, charged and captured the position.

Accompanied by another soldier, he advanced against this position and succeeded in reducing the nest by killing 3 and capturing 7 of the enemy and their guns.