On August 5, 1917 Weigel was appointed a Brigadier General in the National Army and given command of the 151st Depot Brigade, a part of the 76th Division stationed at Camp Devens, Massachusetts.
He commanded the 76th Division from December 17, 1917 to March 14, 1918.

He was next given command of the 56th Infantry Brigade of the Pennsylvania National Guard's 28th Division, which arrived in France on May 14, 1917 and began five weeks of training with British and French forces before going into the line at Château-Thierry and participating in the Champagne-Marne, Aisne-Marne, and Oise-Aisne campaigns.
In recognition of his service during this period, Weigel was awarded the Distinguished Service Medal and Croix de guerre with palm.

Weigel was promoted to Major General on August 8, 1918 and took command of the Eighty-Eighth Division on September 10.
The division relieved a French division in a relatively quiet sector of Haute-Alsace before taking part in the Meuse-Argonne Campaign from November 6–11.
The division remained in France through May 1919 before returning to the United States, where it was demobilized in June.
On August 5, 1917 Weigel was appointed a Brigadier General in the National Army and given command of the 151st Depot Brigade, a part of the 76th Division stationed at Camp Devens, Massachusetts. He commanded the 76th Division from December 17, 1917 to March 14, 1918.
He was next given command of the 56th Infantry Brigade of the Pennsylvania National Guard's 28th Division, which arrived in France on May 14, 1917 and began five weeks of training with British and French forces before going into the line at Château-Thierry and participating in the Champagne-Marne, Aisne-Marne, and Oise-Aisne campaigns. In recognition of his service during this period, Weigel was awarded the Distinguished Service Medal and Croix de guerre with palm.
Weigel was promoted to Major General on August 8, 1918 and took command of the Eighty-Eighth Division on September 10. The division relieved a French division in a relatively quiet sector of Haute-Alsace before taking part in the Meuse-Argonne Campaign from November 6–11. The division remained in France through May 1919 before returning to the United States, where it was demobilized in June.
William Weigel