Following the United States entry into World War II, Harrison was promoted to the temporary rank of Colonel on December 11, 1941, just four days after Japanese attack on Pearl Harbor.
He was appointed Deputy Chief of Strategy & Policy Group, War Plans Division, War Department General Staff and also was given additional duty at General George C. Marshall's Committee on Allocation of Responsibilities which was given the job of figuring out a reorganization of the Army High command.
For his service in this capacity, Harrison was promoted to the temporary rank of Brigadier general on June 26, 1942.

He was subsequently ordered to Camp Butner, North Carolina, where he was attached to the 78th Infantry Division under Major general Edwin P. Parker Jr. as Assistant Division Commander.
Harrison then participated in the training of replacements for units serving overseas and suffered minor injury on an obstacle course in December 1942.
While recuperating, he received a telephone call from Major general Leland S. Hobbs, commanding general, 30th Infantry Division, informing him about his new assignment with Hobbs division.

Harrison was replaced by Brigadier general John K. Rice and appointed Assistant Division Commander under Hobbs, who tasked him with organization of the 30th Infantry Division's training at Camp Blanding, Florida.
Harrison and Hobbs had know each other from West Point, where Hobbs was a member of Class 1915 and also were in the same class at the Army Command and General Staff School in 1937.

Billy Harrison had almost no respect for Hobbs as a leader of the troops.
From Harrison's point of view, Hobbs violated every principle of leadership except one: He demanded obedience and gave it to his superiors.
But in almost every other aspects - from training and disciplining men to planning battle operations in the field.
In short, Harrison described Hobbs as being "stricly [sic?]
a Barracks soldier", who accustomed himself to applause.

Despite this, Harrison remained loyal to Hobbs, who never received anything than support from his Assistant Division Commander.
On the other hand, Harrison benefited from Hobbs's apparent weakness, when he had the opportunity to be with his men during the training and later in combat.

Harrison participated in the training of his troops for the upcoming Tennessee Maneuvers in September-November 1943, where 30th Division showed considerable alertness and skills.
Following the maneuvers, the division moved to Camp Atterbury, Indiana, where it concentrated on preparation for movement overseas.
Following the United States entry into World War II, Harrison was promoted to the temporary rank of Colonel on December 11, 1941, just four days after Japanese attack on Pearl Harbor. He was appointed Deputy Chief of Strategy & Policy Group, War Plans Division, War Department General Staff and also was given additional duty at General George C. Marshall's Committee on Allocation of Responsibilities which was given the job of figuring out a reorganization of the Army High command. For his service in this capacity, Harrison was promoted to the temporary rank of Brigadier general on June 26, 1942.
He was subsequently ordered to Camp Butner, North Carolina, where he was attached to the 78th Infantry Division under Major general Edwin P. Parker Jr. as Assistant Division Commander. Harrison then participated in the training of replacements for units serving overseas and suffered minor injury on an obstacle course in December 1942. While recuperating, he received a telephone call from Major general Leland S. Hobbs, commanding general, 30th Infantry Division, informing him about his new assignment with Hobbs division.
Harrison was replaced by Brigadier general John K. Rice and appointed Assistant Division Commander under Hobbs, who tasked him with organization of the 30th Infantry Division's training at Camp Blanding, Florida. Harrison and Hobbs had know each other from West Point, where Hobbs was a member of Class 1915 and also were in the same class at the Army Command and General Staff School in 1937.
Billy Harrison had almost no respect for Hobbs as a leader of the troops. From Harrison's point of view, Hobbs violated every principle of leadership except one: He demanded obedience and gave it to his superiors. But in almost every other aspects - from training and disciplining men to planning battle operations in the field. In short, Harrison described Hobbs as being "stricly [sic?] a Barracks soldier", who accustomed himself to applause.
Despite this, Harrison remained loyal to Hobbs, who never received anything than support from his Assistant Division Commander. On the other hand, Harrison benefited from Hobbs's apparent weakness, when he had the opportunity to be with his men during the training and later in combat.
Harrison participated in the training of his troops for the upcoming Tennessee Maneuvers in September-November 1943, where 30th Division showed considerable alertness and skills. Following the maneuvers, the division moved to Camp Atterbury, Indiana, where it concentrated on preparation for movement overseas.
William Kelly Harrison Jr.