William H. Wilcox was born in Lempster, New Hampshire, and was residing there when the American Civil War called him into service. He enlisted in the Union Army and was mustered into Company G of the 9th New Hampshire Infantry. By the spring of 1864, the 9th New Hampshire found itself thrust into the brutal Overland Campaign, a series of battles in Virginia that would define the final year of the conflict.

On May 12, 1864, during the Battle of Spotsylvania Court House, Wilcox’s unit was deployed as skirmishers—the forward line of the infantry meant to scout and engage the enemy first. During the heavy fighting, the officers in command of the skirmish line were both wounded and forced to withdraw. Seeing the line falter without leadership, Wilcox stepped forward and took command of the company himself.

Wilcox successfully managed the deployment and maintained the line under fire. In the chaos of the shifting battlefield, he eventually became separated from his specific command. Rather than retreating to the rear, he located another company in the heat of the fight and obtained permission to join their ranks, continuing to engage the enemy throughout the duration of the action. For his gallantry and refusal to leave the field, he was later awarded the Medal of Honor.