Patrick Brennan was born in Dublin, or neighbouring County Kildare, Ireland in 1868, the son of Michael and Catherine Brennan. He was married to Annie Brennan (née Lacey) and they lived with their five children at 55 Langtry Road, Kirkdale, Liverpool, Lancashire, England.
Patrick Brennan was a professional seaman and served on board the Lusitania as a greaser in the Engineering Department and was killed when she was sunk. He was aged 47 years.
His body was not recovered and identified afterwards and as a consequence he is commemorated on the Mercantile Marine War Memorial at Tower Hill, London.
The Liverpool and London War Risks Insurance Association Limited granted a yearly pension to Annie Brennan to compensate her for the loss of her husband which amounted to £38-14s-2d (£38.71) payable at the rate of £2-14s-7d (£2.73) per month.
1901 Census of England and Wales, 1911 Census of England and Wales, Commonwealth War Graves Commission, Cunard Records, PRO BT 334, UniLiv. PR 13/24.