Civil War Union Brevet Major General. He was commissioned as Captain and commander of Company G, 2nd New Jersey Militia on May 1, 1861, serving through the First Bull Run Campaign before being his discharge on July 31, 1861. He then received a commissioned as Captain and commander of Company B, 5th New Jersey Volunteer Infantry on August 28, 1861. On March 7, 1862 he was promoted to Major of the regiment. At this rank he fought with his unit at the Battle of Williamsburg, the Peninsular Campaign, and at the Second Battle of Bull Run. On September 2, 1862 he was detailed to command the 8th New Jersey Volunteer Infantry, whose field officers were either all killed or wounded during Second Bull Run (replacing Captain George Hoffman, who was in temporary command). Promoted to Lieutenant Colonel on October 21, 1862 and Colonel on April 1, 1863. During the Battle of Chancellorsville he was wounded, but was able to return to command during the Gettysburg Campaign. On the Second Day of the Battle of Gettysburg (July 2, 1863) the 8th New Jersey Infantry was detached from its brigade and sent to the Rose Woods next to the Wheatfield as some of the first troops to defend the area from the attacking Confederates. Colonel Ramsey was wounded commanding his regiment, and had to give command to Major John G. Langston (The monument for the 8th New Jersey Infantry Monument, located on DeTrobriand Avenue in the Wheatfield, is inscribed with Colonel Ramsey's name). Recovering from his wounds, he returned to command his unit in the 1864 Overland Campaign, fighting the Battles of the Wilderness, Spotsylvania and Cold Harbor. On June 5, 1864 he was elevated to brigade command, and led the 2nd Brigade, 2nd Division, II Corps in the race to and attack on Petersburg, Virginia. On June 16, 1864 in front of the embattled city he was severely wounded for the third time in the War. After a lengthy recover he returned to command another brigade (1st Brigade, 1st Division, II Corps), which he led in the operations that culminated in the surrender of the Confederates at Appomattox. After the surrender he briefly commanded the II Corps 2nd Division before he was mustered out on July 17, 1865. He was brevetted Brigadier General, US Volunteers on December 2, 1864 for "distinguished services in the present campaign before Richmond Virginia. On March 13, 1865 he received the brevet of Major General, US Volunteers for "gallant and meritorious services during the war". His grave in Arlington National Cemetery is marked with a monument that misspells his last name.