She was born in Cloonee, Co Longford, Ireland on October 13th, 1894.
She was the daughter of Hugh Gilnagh (1865 - 1932), a farmer, and Johanna Duffy (1867 - 1941) who had married around 1892, and she was the sister of: Mary Johanna "Mollie" (b. 1893), Ellen (b. 1895), Thomas (b. 1897), Bridget (b. 1898), Elizabeth (b. 1900), Margaret (b. 1902), Johanna (b. 1904) and Hugh (b. 1905). Another sibling died in infancy. She came from a Roman Catholic family.
The family appear on the 1901 census living at house 18 in Rhine, Cloonee and on the 1911 census at house 6 in the same locale. Her sister Mollie had emigrated to the USA, leaving Ireland on board Laurentic on April 9th, 1911. She lived and worked in Manhattan and soon sent for Kate to join her.
Katie joined the Titanic at Queenstown on April 11th, 1912 as a third class passenger (ticket number 35851 which cost £7, 14s, 8d). Whilst aboard she roomed in cabin 161 on E Deck aft with three other Longford girls, Katie Mullin and the Murphy sisters, Margaret and Kate. She also became acquainted with fellow-Longford passengers James Farrell, Thomas McCormack and the Kiernan brothers, John and Philip among other Irish passengers, including possibly Eugene Daly from Co Westmeath.
On the night of the sinking Katie and other steerage passengers had been enjoying a party in the communal third class areas. A rat scuttled across the floor, sending the party into excited disarray. She and her cabin mates later went to bed when a man with whom they were acquainted aboard rapped their door, telling them to get up as something was amiss with the ship. The four girls dressed and headed out to the upper decks but found their way to the lifeboats impeded by crew members blocking their way and being determined to keep the steerage passengers in their place. When trying to pass through one barrier a crew member halted her but the intervention of James Farrell, who threatened the offending man with a punch if he didn't let the women through, perhaps helped save her life and she later referred to Farrell as her guardian angel. Katie eventually managed to get to a higher deck with the lifeboats tantalisingly close in sight, but she couldn't find her way any further. A man close by offered her a lift up on his shoulders, which she gratefully accepted, and she climbed over the railing to the boat deck. Spying a boat close by she made for it but a crew member again held her back, telling her it was full. Crying out that her sister was in the boat, the crew member relented and let her pass. In years later, Katie recounted that the magnitude of the disaster unfolding at the time escaped her and she naïvely thought that this was the regular way to make it to America.
Katie eventually arrived in the USA and was reunited with her sister Mollie. To reassure her family back home that she was safe, Katie and Mollie had a portrait taken and posted to Ireland. She was eventually joined in America by another two siblings, Margaret (later Mrs Frank Murphy) and William. Her brother William died in 1917. Her sister Mollie (later Mrs Francis Vincent Boshell) died October 12th, 1933.
Kate soon met her future husband, John Joseph Manning (b. 1893), a native of Co Roscommon who worked as a chauffeur. The two were later wed and produced three children: John (b. 1919), Catherine (b. 1921) and Eugene (b. 1927). The family lived in Queens, New York but Kate was widowed on April 19th, 1955.
In later life Kate became a member of the "Titanic Enthusiasts of America," later the Titanic Historical Society, and she appeared on two television programs, To Tell The Truth and the Steve Allen Show and also recalled her experiences to Walter Lord when he was writing A Night to Remember, which told parts of her story. Her picture also appeared in a 1953 Life magazine account of the tragedy.
Kate Gilnagh Manning died on March 1st, 1971 in Long Island City, New York, aged 76, and was buried with her husband in Woodside Cemetery, Queens, New York.