Swift served with the 43rd Infantry in Texas from February to June 1919. He then taught rifle marksmanship at West Point until August 1919, when he joined the 14th Cavalry in Texas. Swift formally transferred from the infantry to the cavalry in November 1919.[1][2] In August 1920, he moved to Fort Des Moines, Iowa with his regiment and served there until March 1921. Swift then served in the Philippines with the 9th Cavalry from May 1921 to August 1922 and the 26th Cavalry (Philippine Scouts) from August 1922 to June 1924. After returning to the United States, he served with the 10th Cavalry at Fort Huachuca, Arizona from July 1924 to July 1927.[3]
Swift was assigned to the Cavalry Rifle Team at Fort Riley, Kansas and Camp Perry, Ohio from June to September 1928. He taught horsemanship at the Cavalry School from June 1929 to August 1933. Swift was promoted to captain in March 1935 and given command of Troop E, 6th Cavalry at Fort Oglethorpe, Georgia from August 1935 to June 1936. He then taught tactics at West Point from June 1936 to June 1938.[3][4]
Swift was assigned to the War Department operations staff in Washington, D.C. from August 1939 to January 1941. He was promoted to major in July 1940. Swift was then assigned to the Legislative Section as an assistant and then as chief from January 1941 to January 1942. He received a temporary promotion to lieutenant colonel in September 1941. Swift was chief of the planning board in the personnel division from January to March 1942. He received a second temporary promotion to colonel in February 1942.[4][5]
Swift was given command of the 14th Armored Regiment, 9th Armored Division at Fort Riley from July 1942 to July 1943. His permanent rank was increased to lieutenant colonel in December 1942. Swift then served as commanding officer of Combat Command A, 9th Armored Division. Finally, he served as deputy chief of staff G-3 for the division before being sent to Europe in November 1943. There Swift was assigned first to Headquarters, First U.S. Army Group and then to Headquarters, Twelfth U.S. Army Group. In October 1944, he was given command of the 66th Armored Regiment, 2nd Armored Division in France for which he was awarded the Silver Star Medal and Bronze Star Medal. In December 1944, Swift was reassigned as assistant commander of the 82nd Airborne Division for which he earned a second Bronze Star and the Order of the Patriotic War First Class when the division came into contact with Soviet Red Army units in May 1945.[5][6] He also received a temporary promotion to brigadier general in March 1945.[1][5]
After the war, Swift returned to Washington, D.C. as chief of the military personnel management group at the War Department from September 1945 to April 1947. He then served as assistant commander of the 2nd Infantry Division at Fort Lewis, Washington from April 1947 to July 1948. His wartime promotion to brigadier general was made permanent in January 1948. Swift briefly served as interim division commander between the departure of Major General Paul W. Kendall in May 1948 and the arrival of Major General Harry J. Collins in June 1948. Sent to Europe in July 1948, he served as commander of United States Forces Austria from October 1948 to January 1951.[1][5][7] His temporary promotion to major general was approved in December 1950.[8]
In February 1951, Swift became commanding general of the 3rd Armored Division at Fort Knox, Kentucky. His assignment was cut short when he was sent to Korea to relieve Major General Joseph S. Bradley as commanding general of the 25th Infantry Division in July 1951. After supervising combat operations there, he was relieved by Major General Samuel T. Williams in July 1952 and awarded the Distinguished Service Medal.[1][9]
Swift subsequently became commander of the III Corps at Fort MacArthur, California. In March 1953, his promotion to major general was made permanent and he took command of V Corps in Europe.[1][10] Swift retired from active duty on 30 June 1954.[11]