A prominent leader of the labor union movement in the U.S. was Samuel Gompers. As the founder and long-time president of the American Federation of Labor (AFL), Gompers championed the rights of workers by advocating for better working conditions, higher wages, and shorter hours. He played a crucial role in organizing labor strikes and negotiations throughout the late 19th and early 20th centuries, promoting a philosophy of pragmatic trade unionism focused on achievable goals rather than radical change. His efforts helped to solidify the legitimacy of organized labor in U.S. society.