During the Korean War, Polk was assigned as G-2 to General Ned Almond's X Corps and later as G-2 to General James Van Fleet's 8th Army, and participated in three campaigns. In August 1951, he returned stateside to attend the National War College, and was later assigned as an instructor at the Army War College. He was then made Chief of Staff of the 3rd Armored Division at Fort Knox, participating in their move to Germany. In July 1956, he was promoted to brigadier general and became assistant division commander.