Entering the United States Military Academy, Kingman graduated second in the class of 1875 and was commissioned in the Corps of Engineers. He served as an instructor at the Military Academy and as the engineer officer of the Army's Department of the Platte based at Fort Omaha. In 1883, he began the construction of roads and bridges in the new Yellowstone National Park. Kingman Pass on the Grand Loop Road between Mammoth Hot Springs and Norris is named for him.