Swift was initially assigned to the 14th Infantry, and soon transferred to the 5th Cavalry, which he joined in the field during the punitive expedition against the Sioux in July, 1876.

He spent several years at posts in the western United States during the American Indian Wars, including assignments in Wyoming, Montana, Nebraska, Idaho, and Colorado.

In his memoirs, he observed: "Civilization approached the American Indians with a Bible in one hand and a paper treaty in the other, a bludgeon in her sleeve, and a barrel of whiskey in her wagon, not to mention the blight that goeth unto the third and fourth generation."

In 1919 and 1920, he was recalled to temporary duty as a lecturer on tactics for Reserve Officer Training Corps units at several colleges and universities.

[2] Camp Swift, Texas, a World War II United States Army training base, was named in his honor.