Michaelis enlisted in the Army on 18 June 1931 and was subsequently appointed to the United States Military Academy.

[3] During the Korean War, Michaelis commanded the 27th Infantry Regiment (the "Wolfhounds") at the Pusan perimeter, for which he received a Distinguished Service Cross.

It was to become an important template used by Ridgway in his conduct of the Korean War once he assumed command from General of the Army Douglas MacArthur.

[citation needed] Ridgeway's policy was to become one of "No more retreat" and he sought to acquire many more commanders like Michaelis as the war continued.

[5] Michaelis described the Turkish Brigade's combat readiness in unflattering terms, according to American historian Clay Blair.

The average Turk soldier in the brigade came from the steppe country of Turkey, near Russia, had probably had only three or four years of school, was uprooted, moved to western Turkey, given a uniform, [a] rifle, and a little smattering of training, stuck on a ship, sailed ten thousand miles, then dumped off on a peninsula – 'Korea, where's that?'