He was involved in the establishment of the United Nations both as a U.S. State Department and U.N. official. Hiss served as executive secretary of the Dumbarton Oaks Conference which formally drew up the U.N. Charter. Hiss was accused of being a Soviet spy in 1948 and convicted of perjury in connection with this charge in 1950. Hiss was the first lawyer ever readmitted to the Massachusetts bar after a major criminal conviction.
In 1944 he became an assistant to Leo Pasvolsky, the first head of the Office of Special Political Affairs.