He was born in 1845/46, in Philadelphia, Pennsylvania. [sources: date: 2 (18 yrs 3 months in March 1864). place: 2]
When he enlisted, he was a hatter. [source: 2]
When he enlisted, he was 5 feet 8 inches tall, and had grey eyes, dark hair, and a light complexion. [source: 2]
On 14 March 1864, he enlisted in company B of the 91st Pennsylvania, at Philadelphia, Pennsylvania. He was enlisted by J A Gregory, and examined by Assistant Surgeon J K Mason. Wilbur F Wampole witnessed his "declaration of recruit". His enlistment was credited to the 5th ward of Philadelphia. [sources: 1, 2]
He is listed on a muster and descriptive roll of a detachment of US volunteers forwarded for the 91st, dated Philadelphia, Pennsylvania, 14 March 1864. But his name is crossed out, and he is not listed on any company muster rolls. [source: 2]
1 index to compiled service records of volunteer Union soldiers who served in organizations from the state of Pennsylvania (Stephen O'Brien)
2 compiled service record, 91st PA (Stephen O'Brien)
I, Stephen OBrien, born in Philadelphia, in the State of Pennsylvania aged Eighteen years, and by occupation a Hatter DO HEREBY ACKNOWLEDGE to have volunteered this Fourteenth day of March 1864, to serve as a Soldier in the Army of the United States of America, for the period of THREE YEARS, unless sooner discharged by proper authority: Do also agree to accept such bounty, pay, rations, and clothing, as are, or may be, established by law for volunteers. And I, Stephen OBrien do solemnly swear, that I will bear true faith and allegiance to the United States of America, and that I will serve them honestly and faithfully against all their enemies or opposers whomsoever; and that I will observe and obey the orders of the President of the United States, and the orders of the officers appointed over me, according to the Rules and Articles of War.
I CERTIFY, ON HONOR, That I have carefully examined the above-named Volunteer, agreeably to the General Regulations of the Army, and that, in my opinion, he is free from all bodily defects and mental infirmity, which would in any way disqualify him from performing the duties of a soldier.
I CERTIFY, ON HONOR, That I have minutely inspected the Volunteer Stephen OBrien previously to his enlistment, and that he was entirely sober when enlisted; that, to the best of my judgment and belief, he is of lawful age; and that, in accepting him as duly qualified to perform the duties of an able-bodied soldier, I have strictly observed the Regulations which govern the recruiting service. This soldier has Grey eyes, Dark hair, Light complexion, is 5 feet 8 inches high.
J A GregoryI, Stephen OBrien desiring to VOLUNTEER as a Soldier in the Army of the United States, for the term of THREE YEARS, Do Declare, That I am Eighteen years and Three months of age; that I have never been discharged from the United States service on account of disability or by sentence of a court martial, or by order before the expiration of a term of enlistment; and I know of no impediment to my serving honestly and faithfully as a soldier for three years.