Business leaders and entrepreneurs shaped American industry in the late 19th and early 20th centuries. Figures like Carnegie, Rockefeller, Ford, Edison, and Morgan revolutionized steel, oil, automotive, electrical, and finance sectors through innovative practices and strategies. These leaders transformed the economic landscape during rapid industrialization, implementing vertical and horizontal integration, mass production, and scientific management. Their legacies continue to influence modern business practices, corporate social responsibility, and ongoing debates about regulation and economic power.