After graduating from law school, Donovan started work at a private lawyer's office. He was a commander in the Navy during World War II. In 1942, he became associate general counsel at the Office of Scientific Research and Development. From 1943 to 1945, he was general counsel at the Office of Strategic Services. In 1945, he became assistant to Justice Robert H. Jackson at the Nuremberg trials in Germany.Nuremberg Trial Proceedings Vol. 1 : Prosecution Counsel, avalon.law.yale.edu, accessed June 5, 2015.
