[1] Williamson remained in the army following the end of World War II, and held several important assignments, including Military Attaché to Canada and later the United Kingdom and commanding general (CG) of the 3rd Armored Division.

[1][2][4] He was a member of the class which produced more than 55 future general officers, including two Army Chiefs of Staff – Joseph L. Collins and Matthew B. Ridgway.

Other classmates include: Clare H. Armstrong, Aaron Bradshaw Jr., Mark W. Clark, John T. Cole, Norman D. Cota, John M. Devine, William W. Eagles, Theodore L. Futch, Charles H. Gerhardt, Augustus M. Gurney, Ernest N. Harmon, William Kelly Harrison Jr., Robert W. Hasbrouck, Frederick A. Irving, Laurence B. Keiser, Charles S. Kilburn, Bryant E. Moore, Daniel Noce, Onslow S. Rolfe, Herbert N. Schwarzkopf, Albert C. Smith, George D. Wahl, and George H.

He returned to the United States in mid-1919 and served as a troop commander at Fort Myer, Virginia, with additional duty as Junior Aide to the White House during the tenure of President Warren G.

[1][4] In August 1922, he was ordered to Harvard University for a year of study, preparatory to detail at West Point, New York, in the newly established Department of Economics and Government, where he subsequently served as an Instructor.

Williamson returned to West Point in July 1932 and served as captain and Assistant Instructor in the Department of Tactics and Personnel Officer of the Academy during the tenure of Lieutenant Colonel Robert C. Richardson.

[1][2][4] The 91st Division was scheduled for the Italian front as part of the U.S. Fifth Army under Lieutenant General Mark W. Clark (a 1917 West Point classmate of Williamson).

Brigadier General Williamson commanded a Task Force of his division during the liberation of the cities of Livorno and Pisa and received the Bronze Star for his leadership.

[4][7] Following the surrender of German forces in Italy at the beginning of May 1945, the 91st Infantry Division remained stationed in that country until late September, when the elements began returning to the United States.

Williamson served in that capacity until the end of May 1949, when he returned to the United States for brief service as Assistant Chief of Staff for Operations (G-3) at Armored Center, Fort Knox, Kentucky.

Williamson was once again appointed CG of the division in October 1951 and remained in that capacity until November 1952, when he was relieved by his West Point classmate, Brigadier General John T.