Richard Byrne was born in 1833 in County Cavan, Ireland, and emigrated to New York in 1844. He appears to have initially joined the army in January 1851, but I was unable to find enlistment documents from his first enlistment. He appears only on post returns as a recruit.

Byrne was enlisted as a private into Company G, 1st (later 4th) U.S. Cavalry by Lt. Robert Ransom on May 21, 1856 at Fort Leavenworth, Kansas. His occupation is listed as soldier, and he’s described as 5’10 ½” tall, with black hair, gray eyes and a fair complexion. He was promoted to corporal and sergeant within Co. G, and by early 1861 was the regimental sergeant major.

On May 14, 1861, Sergeant Major Byrne was appointed a 2nd lieutenant in the 17th Infantry. He applied for a transfer back to the cavalry, which was endorsed by his former commander, now Brigadier General Edwin V. Sumner, and was transferred to the 5th U.S. Cavalry on September 21st. He remained attached to the 4th Cavalry until October 1861, when he joined his company in Washington, D.C.

He served with the 5th U.S. Cavalry throughout the Peninsula campaign, seeing fighting at Williamsburg, Hanover Court House, Ashland, Old Church and White Oak Swamp. Byrne was promoted to first lieutenant on July 17, 1862. During the Maryland campaign, he saw action at South Mountain, Antietam, Shepherdstown, Halltown and Martinsburg.

Massachusetts Governor John Albion Andrews appointed Byrne colonel of the 28th Massachusetts Infantry on September 29, 1862. On October 16, 1862, he was granted an indefinite leave of absence from the 5th U.S. Cavalry to accept the appointment, and assumed command of his new regiment two days later at Nolan’s Ferry. The following month, the regiment was assigned to Colonel Thomas Francis Meagher’s Irish Brigade, Hancock’s Division, II Corps.

Colonel Byrne led his regiment against Marye’s Heights at Fredericksburg, where they lost 157 men killed, wounded and missing of 720 engaged. He fought at the regiment’s head during the Chancellorsville and Gettysburg campaigns.

He was sent back to Massachusetts during the winter of 1863 and spring of 1864 to recruit for the regiment’s depleted ranks. By the opening of the Overland Campaign he had returned to the regiment, and as senior officer present assumed command of the Irish Brigade.

Colonel Byrne was mortally wounded while leading an attack on the Confederate entrenchments at Cold Harbor on June 3, 1864. He was transported to Washington, D.C., where his wife joined him. Richard Byrne died on June 12, 1864. His appointment as a brigadier general of volunteers had been signed by President Lincoln, but he died before it could be officially presented to him. He was buried in Calvary Cemetery, Queens, New York with military honors.

One of the Irish Brigade’s officers, D.P. Conyngham described Byrne as “brave almost to rashness, he always led his men, who knew no fear under his eye; a strict disciplinarian, just to each and all in the exercise of his authority, he commanded the respect and esteem of those under him, and to his efforts is mainly due the high reputation for steadiness and discipline which the Twenty-eighth enjoyed.”

References

Conyngham, D.P. The Irish Brigade and its Campaigns. New York: William McSorley & Co. Publishers, 1867.
Heitman, pg 272.
Price, pgs 495-496.
U.S. Army, Register of Enlistments, 1798-1914, RG 94, NARA.
U.S. Army, Returns from Military Posts, 1806-1916, RG 94, NARA.