Harry Lloyd Hopkins (August 17, 1890 – January 29, 1946) was an American statesman, public administrator, and presidential advisor. A trusted deputy to President Franklin Delano Roosevelt, Hopkins directed New Deal relief programs before serving as the 8th United States Secretary of Commerce from 1938 to 1940 and as Roosevelt's chief foreign policy advisor and liaison to Allied leaders during World War II. During his career, Hopkins supervised the New York Temporary Emergency Relief Administration, the Federal Emergency Relief Administration, the Civil Works Administration, and the Works Progress Administration, which he built into the largest employer in the United States. He later oversaw the $50 billion Lend-Lease program of military aid to the Allies and, as Roosevelt's personal envoy, played a pivotal role in shaping the alliance between the United States and the United Kingdom.

Born in Iowa, Hopkins settled in New York City after he graduated from Grinnell College. He accepted a position in New York City's Bureau of Child Welfare and worked for various social work and public health organizations. He was elected president of the National Association of Social Workers in 1923. In 1931, New York Temporary Emergency Relief Administration chairman Jesse I. Straus hired Hopkins as the agency's executive director. His successful leadership of the program earned the attention of then-New York Governor Roosevelt, who brought Hopkins into his federal administration after he won the 1932 presidential election. Hopkins enjoyed close relationships with President Roosevelt and First Lady Eleanor Roosevelt, and was considered a potential successor to the president until the late 1930s, when his health began to decline due to a long-running battle with stomach cancer.

As Roosevelt's closest confidant, Hopkins assumed a leading foreign policy role after the outset of World War II. From 1940 until 1943, Hopkins lived in the White House and assisted the president in the management of American foreign policy, particularly toward the United Kingdom and the Soviet Union. He traveled frequently to the United Kingdom, whose prime minister, Winston Churchill, recalled Hopkins in his memoirs as a "natural leader of men" with "a flaming soul." Hopkins attended the major conferences of the Allied powers, including the Cairo Conference (November 1943), the Tehran Conference (November–December 1943), the Casablanca Conference (January 1943), and the Yalta Conference (February 1945). His health continued to decline, and he died in 1946 at the age of 55.