A 1915 graduate of United States Military Academy (USMA) at West Point, New York, he was part of "the class the stars fell on"; Dwight D. Eisenhower and Omar Bradley were classmates.

[1] Woodruff was one of the first of his West Point classmates to see action in World War I, when the 2nd Division, embarked for the Western Front on September 17, 1917, as one of the first units of the American Expeditionary Forces (AEF).

[1] Woodruff was a student officer at the Army General Staff College at Langres, France, from November 28, 1917, to February 14, 1918, and then was seconded to the British 8th Division in the Ypres sector.

[6] Woodruff was assigned to United States Army War College in Washington, D.C., with the temporary rank of major from June 17, 1918.

On June 5, 1919, he became a military intelligence officer in the Southern Department, based at Fort Sam Houston, Texas.

[7] Woodruff commanded a rifle company of the 28th Infantry at Fort Ontario, New York, with the rank of major again from August 1, 1924.

[8] In July 1940, Woodruff assumed command of the 2nd Battalion, 23rd Infantry, the same outfit he had served with in World War I.

After being promoted to the temporary rank of colonel on June 26, 1941, he then commanded the regiment, then stationed at Fort Sam Houston, Texas.

Dwight D. Eisenhower, now a four-star general and the Supreme Allied Commander in Europe, was the first, and had been appointed to his new role in December 1943.

[13] Gerow, who was very close friends with Eisenhower and a protégé of General George C. Marshall, the Chief of Staff of the United States Army, managed to retain his position, but Crittenberger and Woodruff were relieved and replaced by two experienced division commanders, Major Generals Charles H. Corlett and J. Lawton Collins respectively.

[9] Upon his return to the United States, Woodruff was deemed to be, in the opinion of Lieutenant General Lesley J. McNair, the commander of Army Ground Forces, "tainted goods and as such was ineligible for another corps".

[16] As a result, he assumed command of the 84th Infantry Division, then in training at Camp Claiborne, Louisiana, from March to June 1944.

[1][15] His welcoming reception in the theater was celebrated at the paratroop headquarters, fueled with five gallons of torpedo alcohol, furnished by United States Navy patrol boat sailors, as the key ingredient for liquid refreshments.

[18] Ironically, Woodruff proved adept at amphibious operations, making a series of twenty-five landings on Mindoro in January and February 1945.

Although in great pain and unable to sleep for two weeks, he concealed the injury for fear of being declared unfit and sent home again.

[9] In November 1945, after World War II had come to an end due to the surrender of both the Germans and the Japanese, Woodruff commanded the I Corps, part of the Eighth United States Army, during the Allied occupation of Japan from April 3, 1946, to February 1, 1948.

[9] From February 1948 to March 1951, Woodruff was deputy commanding general of the First Army at Fort Jay, Governors Island, New York.