The U.S. Army Research Institute is developing and piloting measures of Soldier initiative and perseverance to enhance Soldier mental toughness and readiness for their assigned mission set. Potential uses of the measures are to both assess and develop Soldier initiative and perseverance as part of their individual and collective unit training. In the current research, evidence for construct validity was gathered by administering measures of initiative and perseverance to 151 Soldiers. Additional evidence for construct validity and the usability of the measures in the field was obtained by conducting a pilot test with 10 noncommissioned officers serving in positions of acting squad leader during Medical Simulation Training Center training lanes.