who was the successful commanding general of the northern forces in the civil war
George B. McClellan
short
George B. McClellan
George B. McClellan 1861 photograph by Mathew Brady 24th Governor of New Jersey In office January 15 , 1878 -- January 18 , 1881 Preceded by Joseph D. Bedle Succeeded by George C. Ludlow 4th Commanding General of the United States Army In office November 1 , 1861 -- March 11 , 1862 Preceded by Winfield Scott Succeeded by Henry Halleck Personal details George Brinton McClellan ( 1826 - 12 - 03 ) December 3 , 1826 Philadelphia , Pennsylvania October 29 , 1885 ( 1885 - 10 - 29 ) ( aged 58 ) Orange , New Jersey Political party Democratic Spouse ( s ) Mary Ellen Marcy ( `` Nelly '' ) McClellan Parents George McClellan Mary ( Brinton ) McClellan Alma mater United States Military Academy , West Point , New York Profession Soldier ( General ) Politician Signature Military service Nickname ( s ) Little Mac The Young Napoleon Allegiance United States Union Service / branch United States Army Union Army Years of service 1846 -- 1857 1861 -- 1864 Rank Major General Commands Department of the Ohio Army of the Potomac Battles / wars Mexican -- American War ( 1846 - 1848 ) American Civil War ( 1861 - 1865 ) Battle of Rich Mountain Peninsula Campaign Seven Days Battles Maryland Campaign Battle of South Mountain Battle of Antietam