Porter was commissioned as a lieutenant in the newly formed United States Artillery Battalion on 20 October 1786.
(The modern day 4th Battalion, 1st Field Artillery Regiment is credited with having Porter's company as its lineal ancestor.)
Porter's company was transferred to the 3rd Sublegion when that unit was formed in 1792, and saw service which culminated in the Battle of Fallen Timbers in 1794.
He was retained as a major on 1 April 1802 when the Army was reduced and reorganized in accordance with the Military Peace Establishment Act.
[1] On 12 March 1812, shortly before the outbreak of the War of 1812, Porter was promoted to colonel and placed in command of the Light Artillery Regiment.
After the war, most units of the Light Artillery Regiment were transferred to garrison coastal forts in New England.
An ardent and inflexible patriot, a brave and honorable soldier, an unassuming and virtuous citizen, a generous and faithful friend.
He served his country with distinguished ability and reputation, from the commencement of the Revolutionary war till he expired, full of years and honors, on the 14th of April, A.D., 1822 AE.