The first woman to serve in the U.S. Armed Forces was Opha May Johnson, who enlisted in the Marine Corps Reserve in 1918. Johnson played a crucial role in the early integration of women into military service, paving the way for future generations of female service members. Her enlistment marked a significant step in gender equality within armed forces, showcasing women’s capabilities in traditionally male-dominated roles. Johnson's initiative and participation in military service opened doors for women's expanded roles during and after World War I, reflecting changing societal views on women's contributions to national defense.