Among his fellow graduates included several future general officers like Walton Walker, John Shirley Wood, Gilbert R. Cook, Harry J. Malony, William H. Wilbur, Walter M. Robertson, Franklin C. Sibert and Raymond O. Barton.

He organized the 85th Infantry Division and served as commander from April 1942 to February 1943 until he was succeeded by Brigadier General John B. Coulter, his ADC.

He next took command of XV Corps and served with it through Normandy, France, Rhineland, and Central Europe campaigns.

He became commander of Seventh United States Army, and was in that billet when World War II ended in August 1945.

Haislip died on 23 December 1971, at Walter Reed Army Medical Center after suffering a stroke, and was buried in Arlington National Cemetery.