Early Years

Newton was born in Norfolk, Virginia, on August 24, 1822, the son of Thomas Newton, who served in the House of Delegates (1796–1799) and the U.S. House of Representatives (1801–1833). John Newton graduated from the United States Military Academy at West Point, New York, in 1842, second in a class of fifty-six. His classmates included future Union generals John Pope (ranked 17) and Abner Doubleday (ranked 24) and future Confederate general James Longstreet (ranked 54). After graduation, Newton stayed on at West Point for three years as an engineering instructor before serving in the Army Corps of Engineers. He specialized in military architecture, and from 1846 until 1852 helped build or improve fortifications along the Atlantic Coast and Great Lakes. With fellow Virginians George H. Thomas and Philip St. George Cooke, he participated in the mostly nonshooting Mormon War in 1858. When the Civil War began, he was chief engineer of the Department of Pennsylvania.

Civil War

Like Thomas and Cooke, Newton did not resign from the U.S. Army when Virginia seceded in April 1861. He was commissioned a brigadier general of volunteers in September 1861 and assigned to the defenses of Washington, D.C. During the Peninsula Campaign, Seven Days' Battles, and Robert E. Lee's subsequent invasion of Maryland in 1862, Newton commanded a brigade in the Army of the Potomac's Sixth Corps. And then at Fredericksburg in December he commanded a division. The battle was such a disaster that a handful of Union generals, including Newton, conspired against Burnside. With Union general John Cochrane, Newton actually met with President Lincoln at the White House on December 30, 1862. He could not breach military protocol and tell the president directly that he wanted Burnside fired; instead, as he later told Congress, Newton emphasized "that the troops of my division and of the whole army had become entirely dispirited" and that there was a general "want of confidence in General Burnside's military capacity."

Burnside caught wind of what was going on and even identified the conspirators. He met with Lincoln at the White House on January 24, 1863, with his yet-unreleased General Orders No. 8, which called for the dismissal of Newton, Cochrane, and Joseph Hooker, as well as the reassignment of some others. Burnside also carried a letter of resignation, telling Lincoln he should accept one or the other. The next day, Lincoln accepted Burnside's resignation and, to add insult to injury, in his stead placed Hooker in charge of the Army of the Potomac. Still, there were consequences for such a revolt. Cochrane resigned within a month, citing his health. Other conspirators, including Newton's superiors William B. Franklin and William F. "Baldy" Smith, were forced out of the Army of the Potomac. Newton stayed, but his career suffered nevertheless.

Promoted to major general of volunteers in March 1863, Newton fought well in May at the Second Battle of Fredericksburg during the Chancellorsville Campaign. Two months later, he still was with the Sixth Corps when it and the Eleventh Corps were routed on the first day of the Battle of Gettysburg. Union general John F. Reynolds, the First Corps commander, was killed and Reynolds's old West Point classmate Abner Doubleday took over. By day's end, however, the Army of the Potomac's commander, George G. Meade, had replaced Doubleday with the less-senior Newton, leaving Doubleday livid. According to the historian Stephen W. Sears, Newton was "competent" but "no John Reynolds." Two days later, part of Newton's First Corps formed a portion of the line that faced Pickett's Charge.

Newton continued as a corps commander until the spring of 1864 when his commission as a major general—likely due to his efforts against Burnside—was not confirmed. He was transferred west, where he led a division under fellow Virginian George H. Thomas during the Atlanta Campaign. In October he was transferred again, this time to the out-of-the-way Department of Key West and the Dry Tortugas in Florida. Perhaps in an effort to revive his career, Newton devised a joint army-navy plan he hoped would lead to the surrender of the state capital at Tallahassee. He collected a thousand-man force that included the 2nd and 99th United States Colored Infantry regiments and the 2nd Florida Cavalry (U.S.) and sailed it from Key West and Cedar Key to St. Marks. From there, the men would march to Newport, Florida, and then cross the St. Marks River, destroying property as they went, as well as the railroad that linked the town to Tallahassee, eighteen miles distant.

Confederate resistance, under Brigadier General William Miller, consisted of a small force of local militia, the 2nd Florida Cavalry (C.S.), students from the West Florida Seminary (later Florida State University), and cadets from the Florida Military Institute. They managed to beat the Union troops to Newport and remove the planks from the railroad bridge there, forcing Newton to march eight miles until he found a suitable crossing—a natural bridge where the river actually ran underground for several hundred feet. But Miller beat him there, too, and on March 6, 1865, Newton ordered a full-scale attack, which failed miserably. He suffered 148 casualties compared to 3 killed, and 28 wounded for the Confederates. He blamed the navy for failing to assist him properly.

That same month Newton was awarded the brevet, or honorary, rank of major general of both volunteers and the Regular Army.

Later Years

Newton returned to the Corps of Engineers after the war, and was promoted to brigadier general and became the Army's chief of engineers in 1884. On October 10, 1885, he supervised the detonation of 125 tons of explosives, which cleared the dangerous Hell Gate rock in a narrow strait of the East River in New York City. Newton retired from the Army in 1886, serving as New York City's commissioner of public works (1886–1888) and president of the Panama Railroad Company (1888–1895). He died on May 1, 1895, in New York City and is buried at West Point.