Serving as a company commander in the 58th Infantry Regiment, part of the 4th Division, he saw combat in the Battle of Saint-Mihiel and the Meuse–Argonne offensive, where he was wounded in action on 19 September.

In April 1936, back in the United States, Bolte was assigned to command a battalion of the 13th Infantry Regiment at Fort Devens, Massachusetts.

[3] In 1941, Bolte, by now a lieutenant colonel (having been promoted on 24 December 1941),[3] journeyed to London as head of a group of army observers and, early in 1942, after the United States had entered World War II due to the Japanese attack on Pearl Harbor followed by the German declaration of war on the United States, assumed the position of chief of staff of U.S.

[3] Promoted on 26 April 1943, to the two-star rank of major general,[3] he returned to the United States in 1943 and raised and commanded the 69th Infantry Division in Mississippi.

He led the 34th through several successful actions, including the rupture of the Gothic Line, the winter campaign in the Apennine Mountains, the breakthrough and the capture of the Italian city of Bologna in Operation Grapeshot (codename for the final offensive of the Italian Campaign), the surrender of the Axis forces in Italy on 29 April 1945, and the subsequent occupation of the Northwestern and then the Northeastern sectors of Italy.

Bolte earned two Army Distinguished Service Medals, the Silver Star, the Legion of Merit and the Purple Heart for his exploits during the war.