Artillery Regiment in 1854 around Cape Horn to California and served on the Pacific frontier in garrison duty and campaigns until 1860.

[4] During the Spokane – Coeur d'Alene – Paloos War Captain Keyes was sent ahead with a detachment of dragoons to establish Fort Taylor and a ferry crossing the Snake River for Colonel George Wright's army.

He then served briefly on the staff of New York Governor Edwin D. Morgan until June 25, 1861, overseeing that state's raising of militia.

When Maj. Gen. George B. McClellan's Peninsula Campaign against Richmond was organized in the spring of 1862, Keyes led in unexceptional fashion.

Keyes saw action at Lee's Mill, Yorktown, Bottom's Bridge, Savage's Station, Seven Pines (Fair Oaks), Charles City Cross Roads, Malvern Hill, and Harrison's Landing.

For gallantry at Fair Oaks, Keyes received the brevet of brigadier general in the regular army.

When the army returned to Washington D.C. in early August, Keyes and one of the two IV Corps divisions were permanently left behind on the Peninsula as part of General John Adams Dix's Department of the James.

On March 12, 1863, President Abraham Lincoln nominated Keyes for promotion to the grade of major general, U.S.

Keyes was the author of The Rear Guard at Malvern Hill as part of The Century Company's Battles and Leaders of the Civil War series, as well as Fifty Years' Observation of Men and Events (New York, 1884).