After the war, the Navy assigned Percival to the Boston Navy Yard. Within weeks, he reported for duty on . The captain's clerk, Charles J. Deblois, noted "Lt. P. carries a taught hand, ... He goes by the name of Mad Jack." This is the earliest record of Percival's colorful nickname. Apparently tracing to his intense command style, the application of monikers to military and naval officers was common to the time. After a cruise to South America, he returned to serve as executive office at the Boston yard. In late 1823, he transferred to the frigate on the Pacific station under Commodore Isaac Hull. The two New Englanders were close associates and friends throughout their careers. Hull considered Percival "the best sailor I ever saw!"