He was 20 years old when he was enlisted (4, 7 [21 at death in 1863]). He was born in Port Richmond, [Philadelphia County, Pennsylvania] (7).
He was enlisted and mustered into service on 1 October 1861 (1, 4). He was enlisted at Philadelphia, Pennsylvania (4). He was mustered in, at Philadelphia, Pennsylvania, as a corporal in company I (1, 4).
He was wounded on 3 May 1863 at Chancellorsville, Virginia (1, 4). According to the post-battle report, he was killed in the battle (2). But on 16 May 1863, he was reported gained from missing in action (3).
He died at 4.30 pm on 25 June 1863, of those wounds, in Mower US General Hospital, Chestnut Hill (1 [25 May], 4, 6 [25 June], 7 [25 June]). However, according to his death certificate, he died of typhoid pneumonia with congestion (7). He was then a corporal (1). He was single (7). On 27 June 1863, he was buried at Philanthropic Cemetery, in Philadelphia, Pennsylvania (1, 4, 7).
On 16 July 1890, his mother, Mary Cooker, applied successfully from Pennsylvania for a pension (5, 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) (John R Cooker)
2 consolidated morning report, 91st PA, 7 May 1863 (Corpl Cooker)
3 consolidated morning report, 91st PA, 16 May 1863 (Corpl Cooker)
4 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 28 March 2005 (John R Cooker)
5 pension index, by name (John R Cooker)
6 pension index, by regiment, 91st PA Infantry, company I (John R Cooker)
7 death certificate, Philadelphia, Pennsylvania, 25 June 1863 (John R Cooker)
[I did not find an entry for him in the Ancestry index to the 1890 veteran's census (searched May 2007)]