He was 19 years old when he was enlisted (3, 5). He was born in Philadelphia, Pennsylvania (5).
He was a clerk when he was enlisted (5).
He was 5 feet tall, and had a light complexion, grey eyes, and light hair (5).
He was enlisted on 24 September 1861, at Philadelphia, Pennsylvania (3, 5). He was mustered into service as a private in company K on 24 September 1861, at Philadelphia, Pennsylvania, by Captain Smith (1, 3, 5). He was enlisted for three years, by Captain Casner (5).
He was discharged on 1 April 1865 on surgeon's certificate of disability (1 [1 Apr 1865], 2, 3, 4).
On 30 April 1865, he seems to have been reported absent sick (8).
He also served (perhaps after the war?) in "D Gen[eral] Serv[ice] USA" (6, 7).
On 28 September 1869, he applied successfully for a pension (6, 7).
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)
2 consolidated morning report, 9 June 1864 (Pri Cork [or Cook?])
3 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 25 November 2004 (William J Corke; rolls have 'Cooke')
4 company K, register of men discharged, #20 (William J Cooke)
5 company K, descriptive roll (William J Cooke)
6 pension index, by name (William J Cook)
7 pension index, by regiment, 91st PA Infantry, company K (William J Cook)
8 company K, monthly report, April 1865 (Wm O Conker [?] [uncertain ID])
[I did not find an entry for him in the index on <www.ancestry.com> to the 1890 veterans census (searched April 2006)]