The Marshall County High School junior guard verbally committed to the Hilltoppers Tuesday afternoon.
Harmon, ranked the No. 1 prospect in Kentucky by 247Sports, chose WKU over Kansas, Maryland, Seton Hall and Murray State.
Harmon averaged 24.5 points per game this past season for Marshall County.
The Marshals (23-11) lost to McCracken County 43-42 in the Region 1 championship game.