American lawyer, soldier, and diplomat who directed (1942–45) the U.S. Office of Strategic Services (OSS) during World War II.

Donovan began the practice of law in Buffalo in 1907. In 1916 he served in the New York National Guard on the Mexican border and in World War I he was in France with the 165th Infantry Regiment (formerly the celebrated New York 69th). He advanced to the rank of colonel and was awarded the Congressional Medal of Honor. In 1922 he was appointed U.S. district attorney for western New York. He served as assistant attorney general in the Justice Department from 1924 to 1929. During the 1930s he returned to the practice of law but maintained his political connections both in the United States and abroad. Pres. Franklin D. Roosevelt, in 1940–41, asked Donovan to draft plans for the creation of a central intelligence service for the United States. Donovan was appointed coordinator of information on July 11, 1941. On June 13, 1942, he was named chief of the newly created OSS. This military agency was charged with collecting foreign intelligence and carrying out counterpropaganda and covert action operations; it conducted operations throughout the world, except for Latin America and Gen. Douglas MacArthur's Pacific command, and was most active in Europe.

Donovan was made a brigadier general in 1943. Although he was foremost among the advocates of a peacetime central intelligence service, he declined any role in the Central Intelligence Agency (CIA), which was created in 1947. He served as U.S. ambassador to Thailand in 1953–54.