Barnett's Second World War commands included the 70th Infantry Division and 94th Infantry Division, and his awards and decorations included the Army Distinguished Service Medal, Legion of Merit, and Bronze Star Medal from the United States and the Order of the White Lion from Czechoslovakia.

he rejoined the National Guard at the start of World War I, was commissioned as a captain, and commanded his old company during its initial wartime training and reorganization.

Following the First World War, Barnett served in the United States and was posted to the Philippines as he carried out command and staff assignments.

He graduated from the United States Army Command and General Staff College in 1933, and was trained as an aerial observer.

After World War II, Barnett was reduced in rank to temporary brigadier general and served as assistant chief of staff for First U.S. Army at Governors Island, New York.

[10] With American entry into World War I in April 1917, the 3rd Kentucky Infantry was mobilized in anticipation of being called up for federal service, and Barnett rejoined Company H as a private.

[10] He was then enrolled as a student at the Fort Leavenworth, Kansas United States Army Command and General Staff College, from which he graduated in June 1933.

[10] Barnett was promoted to major after his Staff College graduation, then assigned as a student at Air Corps Tactical School (Maxwell Field, Alabama), where he qualified as an aerial observer.

[10] In anticipation of U.S. entry into World War II, in July 1940, Barnett was promoted to lieutenant colonel, and in August 1940, he was assigned to command 3rd Battalion, 34th Infantry Regiment at Fort Jackson, South Carolina.

[10] The division arrived in Marseille, France during December 1944 and January 1945, after which it moved north and carried out defensive operations along the west bank of the Rhine in the vicinity of Bischweiler.

[26] In mid-January 1945, the division's Infantry regiments moved to an area near Saarbrücken, where it conducted reconnaissance patrols and improved defensive positions.

[27] After penetrating Germany's Siegfried Line defenses along the north bank of the Saar, the 70th Division captured Völklingen, Saarland, and several other cities and towns.

[27] After the European war ended in May 1945, the 70th Infantry Division took part in occupation duties, with posts in Otterberg, Bad Kreuznach, Frankfurt, and Diez.

[10] The surrender of Japan later that month ended the need for additional combat troops for the Pacific War, and Barnett remained in command until the 94th Division was inactivated at Camp Kilmer, New Jersey in February 1946.

His efficient coordination of the activities of the Army with those of the Navy and Marine Corps contributed greatly to the ability of our forces to exert their greatest strength against the enemy and administer a series of crushing defeats.

His initiative, forceful leadership, and broad understanding of combined operations were in keeping with the highest traditions of the United States Military Service.