In July 1860, while commanding companies E and K at a supply depot on Hatch's Ranch near Santa Fe, Frank participated in a three-day skirmish with a band of Comanches.

He successfully defended his position against a force estimated to be ten times larger than his own until reinforcements arrived.

On 9 May 1861, while on a march from El Paso, Texas under the command of Captain Isaac V. D. Reeve, Frank was taken prisoner by Confederate soldiers near San Antonio.

From June 1864 to March 1866, he served on the staff of Brigadier General Philip Cooke in New York City.

After the war, Frank continued on garrison duty, serving primarily in the former Confederate states.

[3][6][7] From July 1886 to November 1888, Frank was assigned to the U.S. Army Artillery School for Practice at Fort Monroe, Virginia.

From August to October 1898, Frank served as commanding general of the 1st Division, 3rd Army Corps.

The USAT General Royal T. Frank was launched in 1908 and served as an inter-island transport in Hawaii.

[13] The USAMP Brigadier General Royal T. Frank (MP-12) was launched in 1942 and served as a mine planter at Fort Miles on Delaware Bay until transferred to the U.S. Navy in 1944.