Following World War I Van Voorhis served in Texas as commander of the 16th Cavalry Regiment, Assistant Chief of Staff of 2nd Cavalry Division, and Assistant Chief of Staff of VIII Corps. In 1924 he was assigned as Executive Officer to the Chief of Cavalry, and in 1929 he graduated from the Army War College. In 1930 Van Voorhis was appointed to command the Army's new experimental mechanized force, first called the 1st Cavalry Regiment, and later the 7th Cavalry Brigade, receiving promotion to Brigadier General. The organization he created and the tactics he developed were vital to the Army's transformation into the modern, mobile armor and mechanized infantry force that was successful in World War II, and with Adna R. Chaffee, Jr. he is recognized as a founder of the Army's Armor branch. General Van Voorhis served as Chief of Staff for the Hawaiian Division from 1934 to 1936. He succeeded Guy V. Henry as commander of Fort Knox in 1936 following Henry's retirement. In July 1938 General Van Voorhis was promoted to Major General and became commander of Fifth Corps Area, with its headquarters in Columbus, Ohio, in October of the same year. In October 1939 he was named to head the Caribbean Defense Command in Panama which was officially activated on 10 February 1940. Van Voorhis was promoted to the rank of lieutenant general in July 1940. In September 1941 Van Voorhis was administratively reduced in rank to major general and reassigned as commander of Fifth Corps Area, where he remained until reaching the mandatory retirement age of 64 in October 1942. He received the Legion of Merit as a retirement award in 1944.
Retirement and death
In retirement he resided in Zanesville, Ohio and Clearwater, Florida. General Van Voorhis died at Walter Reed Army Hospital in Washington, D.C. on January 9, 1956, and was buried in Zanesville's Greenwood Cemetery. His papers, the Daniel Van Voorhis Collection, are part of the Patton Museum at Fort Knox, Kentucky, and an elementary school as well as the largest residential housing area at Fort Knox is named for him.
Citation of Navy Cross: Name: Van Voorhis, Daniel Rank: Colonel, U.S. Army Place of Service: Port of Embarkation, Newport News, Virginia Date: World War I Era The Navy Cross is awarded to Daniel Van Voorhis, Colonel, United States Army, for distinguished service in the line of his profession as Chief of Staff to the Commanding General, Port of Embarkation, Newport News, Va. Citation of Distinguished Service Medal: Name: Van Voorhis, Daniel Service: Army Rank: Colonel War Department, General Orders No. 69 The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Colonel Daniel Van Voorhis, United States Army, for exceptionally meritorious and distinguished services to the Government of the United States, in a duty of great responsibility during World War I. As Chief of Staff at the Port of Embarkation, Newport News, Virginia, Colonel Van Voorhis' services in governing and controlling the Troop Movement Branch at the Port of Embarkation materially aided in the efficient transport of troops and supplies overseas.