This chapter on the U.S. cavalry broadens our investigation of Gulf South rebellion by detailing the stakes, consequences, and ongoing influences of insurgent violence, especially when spearheaded by Indigenous people. From George Washington during the origins of the American republic to Andrew Jackson in the subsequent generation, the image of the man on horseback gained its power from the identity of the individual on the horse. As Jackson left the army and became its commander-in-chief, however, the organization shifted from one based on charismatic leadership to one led by bureaucracy, through the institution of regular units and the creation of standardized doctrine. Although the reformed U.S. cavalry branch bore the outward forms of the French system that Americans studied, reformers sought to apply lessons learned from the generations of Indigenous opponents they faced in the Gulf South borderlands, especially to address the mobility gap that Native people continued to exploit against U.S. agents. The education of U.S. agents in Indigenous warfare ultimately paid dividends in the decades that followed, during the Civil War era and afterward.