His 52 year (1808-1860) military career was one of the longest in the history of the United States Army. He began his military career in 1808, and served in the War of 1812, seeing action in the battles of Chippewa and Lundy"s Lane in 1814, where he was wounded. He was appointed Quartermaster General on May 8, 1818, by President James Monroe.
In 1836, while Jesup was still officially Quartermaster General, President Andrew Jackson detached him first to deal with the Creek tribe in Georgia and Alabama, and then to assume command of all United States. troops in Florida during the Second Seminole War (1837–1842).
His actions in violating truces to capture Seminole leaders, such as Osceola, provoked controversy. At the conclusion of the hostilities, Jesup returned to his official post.
During the Mexican-American War, Jesup traveled from his headquarters in Washington, District of Columbia, to oversee the supplying of troops in Mexico. He served as Quartermaster General for 42 years, having the second longest continual service in the same position in United States. military history (George Gibson served as Commissary General of the United States Army for 43 years, from 1818 until 1861).
He died in office in Washington, District of Columbia, at age 72.
Married Ann Croghan.