A 1920 graduate of the United States Military Academy, he was originally assigned to the Infantry branch and later transferred to Cavalry.

After retiring from the military, Maddox served as assistant to the president of San Marcos Baptist Academy.

[4] Maddox served initially at Fort Stotsenburg, Philippines and received temporary promotion to first lieutenant in 1920.

[1] He began to develop a reputation as an outstanding horseman, which led to participation in numerous equestrian activities, including the Army Horse Show Team.

[16] Assigned as G-3 of Seventh Army, again under Patton's command, Maddox took part in planning and executing the Allied invasion of Sicily in the summer of 1943.

[1] He planned and oversaw execution of Third Army's operations until the end of the war in 1945, and received promotion to temporary brigadier general in November 1944.

[1] Taking command as the Korean War was nearing resolution, Maddox oversaw the division's preparations to return to its home base in Hawaii for post-war reorganization.

[21] In addition, he approved and presented numerous awards and decorations to recognize members of the division for their service and heroism in combat.

[22] During the fall of 1953, Maddox also served as interim commander of I Corps, following the departure of Bruce C. Clarke and prior to the arrival of Blackshear M.

[1] In this position, he commanded 3,000 soldiers who were assigned to advise and assist the military of South Korea as it rebuilt and reorganized following the end of the war.

[25] During his command, which took place as the Cold War was ongoing, the division took part in training and exercises intended to deter the Union of Soviet Socialist Republics from invading Western Europe.

[1] After his brief corps command, Maddox was assigned as chief of staff for United States Army Europe.

[1] In March 1958, Maddox was appointed deputy commander of United States Second Army at Fort Meade, Maryland, where he remained until retiring in January 1959.

[1] Maddox was also active in veterans and military retiree organizations in the San Marcos area, including participating in events to raise money for charity during Armed Forces Day celebrations.

[29] After screening the film, Maddox provided reporters with his impressions of the movie, which were generally favorable, and his recollections of his World War II service under Patton's command.

[37][38] They divorced after World War II, and in December 1949 Maddox married Madeleine (Ehrheart) Chace (1907–2006).