Toward the close of the first session the country was involved in war. He resigned his legislative seat to become captain in the
2nd Kansas Infantry. He participated in the 1861 Southwest Missouri campaign led by
General Lyon, and took part in all the engagements, including the crucial
Battle of Wilson's Creek. In March 1862, Crawford was assigned command of Company A,
2nd Kansas Cavalry, and later commanded of a battalion in the same regiment. With the 2nd Kansas Cavalry he was with General
James G. Blunt in Southwest Missouri,
Arkansas, and
Indian Territory until early in the fall of 1862. During that time he participated in the battles of
Newtonia,
Old Fort Wayne,
Cane Hill,
Bald Peak,
Cove Creek,
Prairie Grove and
Van Buren. At Old Fort Wayne he led his battalion in the charge which resulted in the capture of an entire battery of artillery. On March 12, 1863, he was assigned command of the 2nd Kansas Cavalry and soon afterward joined Blunt at
Fort Gibson for an expedition south through the
Choctaw Nation. This campaign ended with the taking of
Fort Smith, Arkansas, and Colonel Crawford was instrumental in capturing a number of prisoners, wagons, horses, a Confederate paymaster and $40,000 of Confederate money. In November 1863, he was appointed colonel of the
2nd Kansas (Colored) Infantry (later the 83rd U.S. Colored Troops). His regiment participated in the
Camden Expedition and performed admirably in the
Battle of Jenkins' Ferry where it relieved an Indiana regiment and captured a rebel artillery battery consisting of three guns. In March 1864, he joined General
Frederick Steele on an expedition to the Red River under the general command of General
Nathaniel Banks. At
Jenkins Ferry his command lost heavily and his own horse was shot. ==Governor==