Civil War Union Brigadier General. Graduated from the USMA in 1860, placing 40th out of 41 (his classmates included future Confederate Major General Stephen D. Ramseur, and future Union cavalry heroes James H. Wilson and Wesley Merritt). Served on the Colorado frontier from his graduation until June 1862, well after the start of the Civil War. In July 1862 he was sent to the east and was commissioned Colonel and commander of the 11th Vermont Volunteer Infantry. His regiment was assigned to the defenses of Washington, DC, where it was converted into a Heavy Artillery unit. In May 1864, when General Ulysses S. Grant's Overland Campaign needed more men, the 11th Vermont was sent to the Army of the Potomac, and was assigned to the battle-decimated Vermont Brigade (the 11th Vermont had over 2,000 men, more that the whole of the rest of its brigade). During the Battle of Spotsylvania, Colonel Warner was shot in the neck while walking along Union earthworks, encouraging his men. Sent to Washington, DC to recover, he participated in the July 1864 repulse of Confederate General Jubal Early's strike against the capital. Brevetted Brigadier General, US Volunteers in August 1864, he was assigned to command a brigade in General Philip Sheridan's Army in the Shenandoah Valley. He would render distinguished service at the Battles of Fisher's Hill and Cedar Creek (where his brigade was one of the few organized Union forces still on the line before Sheridan's famous rallying ride). He would serve up to the April 1865 Appomattox Campaign. He was promoted to full rank Brigadier General, US Volunteers on May 8, 1865 and received a brevet of Brigadier General, US Regular Army. Resigning from the Army in 1866, he would go on to hold administrative positions in New York City until his death in 1897. He was the great-uncle of Civil War author and historian Ezra Warner, who wrote the "Generals in Gray" and "Generals in Blue" reference works.