He participated in the Reserve Officer Training Corps (ROTC) program, graduated from NC State, being commissioned as a second lieutenant in the Infantry Branch of the United States Army in 1917, after the American entry into World War I. Lee served in World War I with the American Expeditionary Forces (AEF), which was commanded by General John J. Pershing, on the Western Front.

[7]He trained the 101st in the United States from its creation until being sent to England in September 1943 to prepare for the Allied invasion of Normandy, codenamed Operation Overlord.

On February 5, 1944, a damp, wet and cloudy day, Lee was on his way to observe a training exercise by the 401st Glider Infantry Regiment, commanded by Lieutenant Colonel Joseph "Bud" Harper.

Harper managed to secure the services of a truck nearby and Lee was evacuated to the 302nd Field Hospital, where doctors diagnosed a serious heart attack.

Although the Army wanted to send him back to the United States for better treatment, Lee refused, believing, in vain, that he might return to the 101st, where Lieutenant General Omar Bradley had promised to hold his command.

[8] Lee remained in hospital until March, when he had a second heart attack and was returned to the United States, where he would be retired from the Army for reasons of ill health in late 1944.

But Eisenhower selected Brigadier General Maxwell D. Taylor, commander of the 82nd Airborne Division Artillery, with combat experience in Sicily and Italy under his belt, to lead the 101st into battle.