He entered the United States Military Academy in 1917, after the American entry into World War I, and was commissioned as a second lieutenant into the Coastal Artillery Branch, and later transferred to the Cavalry Branch of the United States Army.

He later served as an instructor at the U.S. Army Cavalry School and on the General Staff of the War Department.

From 1942 to 1943 Deputy Chief of Staff Allied Forces Headquarters (AFHQ) before being assigned as Assistant Division Commander (ADC) of the 1st Infantry Division, which took part in the Normandy landings on 6 June 1944, and the subsequent Battle of Normandy that followed.

Wyman died at Walter Reed Army Medical Center in Washington, D.C., on 29 March 1969, aged 71, and was buried in Arlington National Cemetery.

[3] Wyman's awards and decorations include the Distinguished Service Cross, the Army Distinguished Service Medal with two oak leaf clusters, the Silver Star, the Legion of Merit, the Bronze Star Medal with "V" device and the Order of the Patriotic War First Class (USSR) which he received when Commanding General, 71st Infantry Division, as the division linked up with Soviet Red Army units at war's end.