John Henry (Harry) Hesketh was born in Kirkdale, Lancashire, England on 28 January 1879.
He was the son of Henry Hesketh (1848-1919), a railway engine driver, and Mary Griffith (1849-1926), Lancashire natives who had married in St George's Church, Everton on 1 October 1871. One of seven surviving children (from a total of eight) born to his parents, John's siblings were: Mary Louisa Ellen (b. 1873), Frances Jane (b. 1875), Charlotte Eleanor (b. 1876), Thomas Griffith (b. 1881), Josephine Taylor (b. 1887) and Gertrude Adelaide (b. 1890).
He first appears on the 1881 census living at 24 Croylands Street in Kirkdale. By the time of the 1901 census he was described as a marine engineer and still living with his family, then at 26 Barlow Lane in Kirkdale.
Hesketh had been apprenticed as an engineer from the age of 14 before joining the White Star Line, commencing his seafaring career as Sixth Engineer aboard the Afric. He latterly served aboard a number of the company's vessels, including Cedric, Persic, Medic and Laurentic and was involved in the salvage of the Seuvic following that ship's grounding. He had responsibility for the refrigeration machinery aboard the Majestic and was instrumental in improving the quality of the refrigerated cargo provision offered by White Star. He was the youngest acting Second Engineer in the company. By the time of the 1911 census John was still living with his family, by now at 80 Garnett Avenue, Kirkdale. He was unmarried.
When he signed on to the Titanic's maiden voyage on 9 April 1912, he gave his address as 80 Garnett Avenue [Liverpool] and his previous ship as the Olympic. As a second engineer he could expect monthly wages of £18.
Hesketh was in Boiler Room 6 when the Titanic struck the iceberg and he barely managed to shut the dampers (shutting off the flow of air to the fires) when he heard a sound like a gunshot. He and leading stoker Frederick Barrett were suddenly hit by a jet of icy water and they ran aft and managed to clamber through the doorway of the tunnel into boiler-room 5 as the watertight door closed. The remaining men including Fireman George Beauchamp raked the fires before escaping to safety.
John Henry Hesketh died in the sinking and his body, if recovered, was never identified.
His estate at death was worth £447,10s and was administered to his father Henry on 8 July 1912.