Mouton's brigade was used as the lead unit in the Confederate attack at the Battle of Mansfield. While leading his brigade in a charge against the Union position, Mouton was shot and killed. Historian John D. Winters reports on the battle: "On his horse, Mouton made a perfect target, and a Federal marksman dropped him from his saddle. The gallant Polignac now rode forward and took over the command. With tears of grief and rage in their eyes, the yelling men followed Polignac. They ran on through the deadly hail, determined to avenge the death of their leader. ... Mouton's division lost about one third of its total strength." Mouton's death was lamented by General Taylor, who said, "Above all the death of the gallant Mouton affected me ... modest, unselfish, and patriotic. He showed best in action always leading his men." He was first buried on the battlefield but was moved in 1874 to St. John's Cemetery in Lafayette, Louisiana.