Hardtner was born to E.J. Hardtner and the former Emma Schraeder, both of German ancestry, in Pineville, located across the Red River from the larger Alexandria, Louisiana.
In addition to his forestry endeavors, Hardtner was a vestryman in the St. James Episcopal Church in Alexandria,[REF] and was active in the Masonic lodge and the Good Roads Association, a transportation lobbying group active in several states [REF].