Thomas Jack was born in Falkirk, Stirlingshire in Scotland on 17 May 1918, the eldest son of Thomas and Elizabeth Jack of 15, Parkhall Drive, Maddiston, Stirlingshire. He was from a large family with two brothers (Robert & Willie) and four sisters (Georgina, Peggy, Lizzie & Annie).

Thomas Jack joined the Royal Navy and, by June 1944 he was a Leading Seaman serving in HMS SICKLE. On 4 June 1944, SICKLE took part in a surface gun action in the Mediterranean in which two crewmen were wounded and one (AB Blake) was lost overboard. AB Blake was rescued by German Forces and, accidentally and very luckily, became the only survivor of HMS SICKLE.

The submarine was lost with all hands about two weeks later probably by striking a mine in the Antikithera Channel, Greece, on or around 18 June 1944. Although he had been reported missing, presumed drowned, in 1944 his death was not confirmed to the family until June 1945 and a notice was placed in The Falkirk Herald and Scottish Midland Journal of Saturday 30 June 1945 by his family.

Thomas Jack is commemorated on the Portsmouth Naval Memorial on Panel 81 Column 2.