Union general during the American Civil War (1861–65) who was particularly active in the early years of fighting around Washington, D.C.

Franklin graduated from the U.S. Military Academy at West Point, N.Y., in 1843 and served in the Mexican War (1846–48). When the Civil War broke out, he was appointed a brigadier general of volunteers and fought at the First Battle of Bull Run (July 1861). He was then advanced to division commander in the Army of the Potomac and served in the Peninsular Campaign in 1862.

Franklin was a major general at the Battle of Antietam, Md. (September 1862); he was later partially blamed for the disastrous defeat at the Battle of Fredericksburg (Fredericksburg, Battle of) (December 1862) by both his commanding officer, General A.E. Burnside, and a congressional committee on the conduct of the war. However, the committee did not have access to a copy of Burnside's orders to his subordinates, which were acknowledged to be confusing. Franklin was inactive for some months before serving inauspiciously in the Southwest. He resigned from the army in 1866 and was engaged in business at Hartford after the war.