He participated in maneuvers in the Big Bend area of Texas, trained remounts and cavalry recruits and assisted in the care and feeding of thousands of Mexicans whose homes has been inundated in the 1927 flood of the Rio Grande.

He participated with his troop in annual maneuvers with the United States Army Infantry School students at Fort Benning, Georgia.

Herren, as part of that effort, moved to Gatlinburg, Tennessee, where he organized and supervised the construction, supply and operation of 17 CCC camps in the Great Smoky Mountains National Park.

During this period he attended short courses in Chemical Warfare, Sanitation, Food Service, Public Relations and other subjects of value to military officers.

Upon the completion of that course in 1936, he returned to the United States Army Cavalry School, at Fort Riley, Kansas as an instructor in the Department of Tactics from 1937 to 1938.

At that time "Mechanization" was introduced into the school curriculum and the tactics and techniques developed by Herren's department were later used by General George Patton and his armored units in World War II.

During the summer of 1938 Herren was assigned to the United States Army Infantry School at Fort Benning, Georgia where he was a cavalry instructor and chairman of the animal management and transportation committee.

In 1942 Herren was promoted to colonel and assigned to the 106th Cavalry Regiment of the Illinois National Guard then in training at Camp Livingston, Louisiana.

As the regiment was deployed to Europe in 1943, Herren returned to the Cavalry School at Fort Riley as its commandant and was promoted to brigadier general in 1944.

As Task Force HERREN it undertook combat missions with the Seventh United States Army in northeast France, mostly in the Alsace-Lorraine region.

Task Force HERREN fought in numerous engagements in Operation Nordwind and along the Rhine until remaining units of 70th Division arrived.

In late 1949 Herren became 2nd Brigade commander for the 1st Cavalry Division in Tokyo for six months before returning to the United States where he was promoted to major general and appointed to staff for the Secretary of Defense as Chief of Special Services in 1950.

In this position he directed and supervised all United States Armed Forces Institute education programs throughout the Army, arranged for off duty classes and overseas instruction.

Again Herren commanded logistical support and supply for U.S. Army forces and military dependents in over two dozen posts, sub-posts and training areas in northern Germany.

NORCOM consisted of the former Frankfurt and Wuerzburg districts and military posts, Bamberg subpost for Nuernberg, and the airbases at Rhine-Main and Wiesbaden.