He received an appointment to the United States Military Academy in West Point, New York, and graduated 22nd of 52 cadets in the Class of 1853.

[4] During the April 1861 crisis at Fort Sumter in Charleston, South Carolina, Tyler was part of a hastily assembled relief force that tried unsuccessfully to reinforce the beleaguered garrison.

The regiment served in the Peninsula Campaign, and Tyler commanded the siege train of the Army of the Potomac under Maj. Gen. George B. McClellan.

In early 1864, Tyler was assigned command of a division of infantry consisting entirely of heavy artillery regiments, which he led at Harris Farm in the Battle of Spotsylvania Court House, where it was attached to II Corps.

He then led a brigade in 2nd Division, II Corps, at the Battle of Cold Harbor and was severely wounded by a bullet in his ankle[10] which incapacitated him from any further field duty during the war.

After a 6 month recovery, Tyler served in an administrative role in command of the District of Delaware and the Eastern Shore with his headquarters in Philadelphia.

Tyler received the brevet rank of major general of volunteers for "great gallantry at the Battle of Cold Harbor".

In 1866 he mustered out of volunteer service and was commissioned as a lieutenant colonel in the regular army, serving as deputy Quartermaster General in several locations.