As a civilian, he was one of the founders of the American Society of Civil Engineers and Architects and was responsible for numerous railroads and aqueduct construction projects in the northeastern United States.

[1] His family had roots in the founding of Rhode Island and in the American Revolutionary War, including General Nathanael Greene, George's second cousin.

While assigned to Fort Sullivan in Eastport, Maine, in 1833, tragedy struck Greene's family: Elizabeth and all three of their children died within seven months, probably from tuberculosis.

To ease the pain on his mind and to escape the isolation and loneliness of peacetime Army garrison duty, he immersed himself in study of both the law and medicine, coming close to professional certification in both by the time he resigned his commission in 1836 to become a civil engineer.

[5] Greene built railroads in six states and designed municipal sewage and water systems for Washington, D.C., Detroit, and several other cities.

In New York City, he designed the Croton Aqueduct reservoir in Central Park and the enlarged High Bridge over the Harlem River.

Governor Edwin D. Morgan, although initially reluctant to appoint Greene because of his age, saw his 13 years of regular army experience as a solution to his political/military problem.

[8] On April 28, 1862, Greene was appointed brigadier general of volunteers and served on the staff of Maj. Gen. Nathaniel Banks in the Shenandoah Valley campaign against Stonewall Jackson.

Gen. Joseph K. Mansfield was killed shortly after the fighting began, Greene led a crushing attack against the Confederates near the Dunker Church, achieving the farthest penetration of Maj. Gen. Stonewall Jackson's lines of any Union unit.

Under immense pressure, Greene held his small division (only 1,727 men engaged at the start of the day)[10] in advance of the rest of the army for four hours, but eventually withdrew after suffering heavy losses.

On July 2, 1863, Maj. Gen. George G. Meade shifted almost the entire XII Corps from the Union right to strengthen the left flank, which was under heavy attack.

Greene's lone brigade of 1,350 New Yorkers (five regiments) was left to defend a one-half-mile line on Culp's Hill when an entire Confederate division attacked.

Gen. Alpheus Williams, acting corps commander on July 2, commended Greene for his "skill and judgment" in this defense, especially in his using the "advantages" of his position.

However, Greene's contributions to this critical battle have never been widely heralded, principally because of a dispute between Meade and Slocum over the filing of their official reports.

At the Battle of Wauhatchie, during a surprise night attack by the Confederate forces, Greene was wounded in the face, with his jaw crushed and some teeth carried away.

After six weeks of medical leave, he was assigned to light court-martial duty until January 1865, when he was sent to join Maj. Gen. William T. Sherman's army in North Carolina.

[16] At the very end of the war Greene was in command of the 3rd Brigade in Absalom Baird's 3rd Division, XIV Corps, and participated in the capture of Raleigh and the pursuit of Gen. Joseph E. Johnston's army until its surrender.

The best that Congress was willing to do was arranged by Congressman and Gettysburg veteran Daniel E. Sickles of New York, a first lieutenant's pension, based on the highest rank Greene had achieved in the regular army.

Veterans in the Military Order of the Loyal Legion of the United States (MOLLUS) declared that he was the oldest lieutenant in world history.

Their oldest son, Lieutenant Samuel Dana Greene, was the executive officer on the ironclad ship USS Monitor during the Battle of Hampton Roads.

A description of George Sears Greene from Lt. George K. Collins of the 149th New York Infantry sums up the general:[21] He was a West Point graduate, about 60 years old, thick set, five feet ten inches high, dark complexioned, iron gray hair, full gray beard and mustache, gruff in manner and stern in appearance, but with all an excellent officer and under a rough exterior possessing a kind heart.