After some years of teaching, in 1934 White joined the U.S. Treasury as an economist, quickly winning the trust of Secretary Henry Morgenthau Jr., although the latter never shared White's enthusiasm for countercyclical Keynesian economic theories. In 1936 White helped to negotiate the Anglo-American currency stabilization agreement and a U.S. silver purchase accord with China. A staunch antifascist, by early 1939 he supported economic sanctions against Germany and hoped to entice the communist Soviet Union into an anti-Nazi coalition.
As Morgenthau's chief advisor during World War II, White supervised aid to Jiang Jieshi's Guomindang (GMD, Nationalist) government in China but by the war's end had concluded that the regime was too corrupt and ineffective to survive. Taking the lead in U.S. Treasury postwar planning, White helped to draft Morgenthau's abortive 1944 proposal to divide and de-industrialize Germany. White's major efforts, however, focused on creating a postwar international monetary system that would foster the revival of world trade and prevent future wars by precluding the competitive nationalist economic rivalries of the 1930s. Together with similar proposals put forward by the British economist John Maynard Keynes, White's plan for a United Nations (UN) stabilization fund and a bank for reconstruction to stimulate economic development and maintain stable international exchanges, which White drafted in 1942, laid the groundwork for the 1944 Bretton Woods Conference that established the International Monetary Fund (IMF) and the World Bank.
In early 1946, White became the IMF's first American executive director. Shortly before, Elizabeth Bentley, a former communist agent turned Federal Bureau of Investigation (FBI) informant, claimed that during the war White had passed on classified Treasury documents to Soviet agents, allegations that recently released Venona decrypts of intercepted wartime Soviet telegraphic communications appear to substantiate. In March 1947 White quietly resigned his IMF position. He testified on 13 August 1948 and denied that he had ever been either a communist or a Soviet agent after Bentley publicly told the House Un-American Activities Committee (HUAC) that White had been a Soviet operative, charges that renegade Soviet agent Whittaker Chambers repeated after White's death from a heart attack three days later, on 16 August 1948, while vacationing near Fitzwilliam, New Hampshire.
Craig, Bruce R. Treasonable Doubt: The Harry Dexter White Spy Case. Lawrence: University Press of Kansas, 2004.; Rees, David. Harry Dexter White: A Study in Paradox. New York: Coward, McCann and Geoghegan, 1973.; Van Dormael, Armand. Bretton Woods: Birth of a Monetary System. London: Macmillan, 1978.