Jacob was born in 1923 in Hackney, London to Dublin born Samuel and Yetta nee Kosky and he had an older sister Daphne. Their father Samuel worked as a dental surgeon who was a captain in the Jewish Lad’s Brigade Royal Army Medical Corps in both wars. In 1939 the family were living at 62 Kingsland High Street in Dalston, Hackney before moving to Shoeburyness.

Jacob enlisted in 1942. He was killed on 30 November 1945 and his death certificate states that he died in the Royal Air Force Hospital in Wroughton, due to war operations. His obituary in the Jewish Chronicle says that he died from multiple injuries as the result of an aircraft accident.