His foreign awards included the French Legion of Honor (Chevalier) and Croix de Guerre with palm, and the Distinguished Service Order from the United Kingdom.

[1][2] He served for two years, including federalization for duty during the Mexican Border War, and advanced in rank from private to corporal.

[2][4] Earnest was regarded as one of the army's best horsemen, and in addition to playing polo, during his career both his wife and he took part in numerous horse shows and competitions.

[4] When he returned in 1926, he was assigned to the United States Army Command and General Staff College as an instructor in equitation.

[4][8][9] After Civilian Conservation Corps duty in Missouri during 1933, he was a student at the Command and General Staff College, from which he graduated in June 1934.

[4] From 1938 to 1939, Earnest was a student at the Army Industrial College (now the Dwight D. Eisenhower School for National Security and Resource Strategy).

[12] In the early 1940s, the army again began to expand, this time in anticipation of U.S. entry into World War II, and Earnest was promoted to temporary colonel in December 1941.

[4][12] Earnest was promoted to temporary brigadier general in February 1943, and he led the 1st Tank Destroyer Brigade during its final training at Camp Claiborne, Louisiana and departure for combat in Europe.

[4] After additional training in England, in August 1944, the brigade landed in France as part of Third United States Army.

[4] During combat in Daoulas and Crozon, Earnest commanded an ad hoc unit, Task Force A, which included his brigade as well as artillery, armor, infantry, and air support.

[4] In addition, the reserve included many looted art treasures, among them paintings by Anthony van Dyck, Rembrandt, and Pierre-Auguste Renoir.

[4] Beginning in May 1945, the 90th Infantry Division was headquartered in Weiden in der Oberpfalz as it performed post-war occupation duty in Bavaria.

[4] In 1947, an assessment of his wartime experience resulted in Earnest receiving constructive credit for attendance at the National War College.

Under his direction, the 90th Division, in 47 days of continuous contact with the enemy advanced some 400 miles across major rivers, mountains and difficult terrain.

General Earnest's bold decisions, based on sound tactical insight, made possible rapid thrusts which completely disorganized the enemy and attained valuable objectives with minimum loss."