Following post-war occupation duty in Germany, Beiderlinden returned to the United States, where his assignments included battery command and assistant professor of military science at the University of Missouri.

Beiderlinden continued in assignments of increasing rank and responsibility leading up to World War II, including a posting in the Philippines.

During the early stages of the Korean War, he assumed responsibility for providing troop reinforcements during combat, as well as the evacuation of non-combatants.

[4][5] While in college, Beiderlinden was president of Lambda Epsilon, an honor society for science students, as well as an assistant in the Biology department.

[5][6] In August 1917, Beiderlinden joined the military for World War I when he enlisted as a private in the Missouri National Guard's Truck Company 5, Motor Transport Train.

[1] The unit was subsequently activated for federal service as the 110th Supply Train, and Beiderlinden continued to serve until November, attaining the rank of private first class before being discharged so he could accept a commission.

[1] He attended the Citizens' Military Training Camp held at Fort Sheridan, Illinois, where he was assigned to Second Battery, 11th Regiment.

[9] Beiderlinden was then assigned to the 30th Separate Artillery Brigade, with which he served in a variety of positions on several fronts until the Armistice of November 11, 1918 ended the war.

[9] Beiderlinden was assigned to the 83rd Field Artillery Regiment following his wartime service, and he received his commission as a first lieutenant in the regular army in July 1920.

[9] In September 1935, Beiderlinden began attendance at the United States Army Command and General Staff College, and he graduated in June 1939.

[9] In February 1943, Beiderlinden was assigned to command the 44th Division Artillery at Fort Lewis, and in March he was promoted to brigadier general.

[9] The division took part in combat in Western Europe throughout 1944 and early 1945, and Beiderlinden became the subject of international headlines in March 1945, when he helped save Heidelberg from bombing by persuading Nazi troops to withdraw.

During the early crucial stages of the Korean campaign, he initiated the prompt readjustment of military and civilian personnel to meet the strong challenge inherent in sudden armed conflict.

He evolved a system that continuously provided reinforcements to units in Korea and superbly directed the evacuation to Japan of non-Korean nationals whose survival was threatened by the invading forces.

His keen foresight early in the campaign enabled him to direct the initiation of a combat rotation program which, when the situation in Korea permitted, was ready for immediate implementation.