He was born in Philadelphia, Pennsylvania (8). He was 42 years old when he was enlisted (8).
He was a butch[er] when he was enlisted (8).
He was 5 feet 10 inches tall, and had a dark complexion, hazel eyes, and brown hair (8).
He was enlisted and mustered into service on 17 October 1861 (1, 8). He was enlisted for three years, at Philadelphia, Pennsylvania, by Captain Smith (8). He served as a private in company I (1).
He deserted on 3 January 1862 (1). The 26 April 1863 report claims he was gained from desertion, and was being held in arrest at Fort Delaware (2). The extant consolidated morning reports continue to report one enlisted man in company I absent in arrest or confinement--presumably Cooker--through 11 June 1863 (3).
The next extant report, from 28 July 1863, reports him dropped as missing in action in the campaign, probably after 11 June 1863 (4).
On 6 November 1863, he was reported regained from desertion (5).
On 30 January 1864, he deserted, at Philadelphia, Pennsylvania (7, 8, 9 [but note date]).
On 12 March 1864, he was reported under arrest (6).
1 Bates, Samuel Penniman. History of Pennsylvania volunteers, 1861-5. Harrisburg: B. Singerly, state printer, 1869-71. 5 volumes. 'Ninety-first regiment', volume 3, pages 186-233. (In the roster) (Henry M Cooker)
2 consolidated morning report, 91st PA, 26 April 1863 (Private Cooker)
3 consolidated morning report, 91st PA, 11 June 1863 (not named)
4 consolidated morning report, 91st PA, 28 July 1863 (Private Cooker)
5 consolidated morning report, 91st PA, 6 November 1863 (Priv Cooker [?])
6 consolidated morning report, 12 March 1864 (Cooker)
7 company I, register of deserters (Henry Cooker)
8 company I, descriptive roll, #42 (Henry Cooper [sic])
9 consolidated morning report, 91st Pennsylvania, 28 December 1864 (Cooker [sic])