Following the Japanese attack on Pearl Harbor and the United States entry into World War II, Wickersham was promoted to the temporary rank of Brigadier general in January 1942 and assumed duty as Commandant of newly established School of Military Government located at the University of Virginia in Charlottesville, Virginia. While in this capacity, he was subordinated directly to the Provost Marshal General of the Army, Major general Allen W. Gullion and was responsible for training of officers in future detail in connection with Military Government and Liaison. Graduates assisted commanders in foreign fields in their relations with civilians. While in that assignment, Wickersham was also on special duty as an Advisor on Military Government affairs in Africa, Sicily, and Italy. For his service in that assignment, Wickersham was decorated with Legion of Merit.