This dissertation argues that between 1914 and 1924, U.S. Marines made manhood central to the communication of their image and culture, a strategy that underpinned the Corps’ effort to attract recruits from society and acquire funding from Congress. White manhood informed much of the Marines’ collective identity, which they believed set them apart from the other services. Interest in World War I, the campaigns in Hispaniola, and the development of amphibious warfare doctrine have made the Marine Corps during this period the focus of traditional military history. These histories often neglect a vital component of the Marine historical narrative: the ways Marines used masculinity and race to form positive connections with American society. For the Great War-era Marine Corps, those connections came from their claims to make good men out of America’s white youngsters. This project, therefore, fits with and expands the broader scholarly movement to put matters of race and gender at the center of military history. It was along the lines of manhood that Marines were judged by society. In France, Marines came to represent all that was good and strong in American men. In Haiti and the Dominican Republic, however, they demonstrated the ironies and weaknesses of American manhood through cruel and inhumane treatment of natives. Marines maintained positive connections with society through this controversy regardless. Throughout the Great War-Era, Marines promoted a style of manliness that emphasized popular Victorian notions of honor, courage, selflessness, self-control, hard work, and strength. In doing so, they kept traditional ideals of manhood at a time when American men’s culture had begun to shift toward a newer form of masculinity that valued consumption over production and appearances over character. In the Great War Marines presented themselves as the knightly saviors of civilization. In Hispaniola they portrayed themselves as the enforcers of peace and law whose manhood was far superior to the Haitians’ and Dominicans’. As Marines promoted themselves as a man-making institution, one that could turn Americans into good citizens, they demonstrated how adaptive their manly image could be through peace, war, and foreign occupation duty.