Comanche was a 15 hand bay gelding, thought to be part mustang and part Morgan. He was bought by the U.S. Army in 1868 in St. Louis, and sent to Fort Leavenworth, Kansas. He was a good looking horse, and instead of being kept with the regular cavalry, Captain, Myles Keogh, bought him for $90 to use as his personal mount. He normally rode his horse Paddy on marches, Comanche following with the other extra horses. Comanche was the horse Captain Keogh rode into battle, the horse being fresh because he was only mounted at the last moment before the fighting began. He was a war horse.

Captain Keogh was in Custer's 7th Cavalry. In the fall of 1868, his unit fought the Comanche tribe in Kansas. During the battle, the horse was wounded, but the Captain did not know that and continued to fight from his back until the battle was over. Afterward, he discovered an arrow broken off in the horse's hindquarters. The wound was treated and after the horse recovered, he had earned the name Comanche for his bravery in continuing to carry his master despite his own pain.

In 1870 during a battle again against the Comanche tribe, the horse was wounded in the leg. He was lame for over a month this time, but recovered. Then, in 1871, Comanche was wounded in battle once more, this time in his shoulder, and once again, he recovered quickly. The cavalry was very proud of this brave horse who continued to go into battle despite being wounded so many times.

In 1876, Captain Keogh rode Comanche into the valley of the Little Big Horn and the battle known as Custer's Last Stand. This time they were fighting the Soux and Cheyenne tribes, and it was the last great battle for the Native Americans. They defeated the 7th cavalry and killed every soldier. The only member of the 7th cavalry left alive after the battle was Comanche.

Comanche was found two days after the battle with many wounds, and was very weak and barely able to stand. He was taken in a steam boat to Fort Lincoln, where he was so weak he had to be supported by a sling. He was nursed back to health, once again recovering from his battle wounds.

Comanche was officially retired and it was ordered that no one would ever ride him again. He was called "the Second Commanding Officer" of the 7th Cavalry. His only duties were to be lead in the front of official parades occasionally. It is said he developed a fondness for beer in his later years, and was such a pet at the fort that he was often indulged in this habit. He lived to the age of 29, and when he died his body was mounted and put on display at the University of Kansas, where it stands to this day.