Morris was born on 6 May 1910 in Liverpool. His Jewish family had emigrated to escape pogroms in Poland. Arriving by boat in Liverpool, the family adopted the surname of the ship's captain. His family moved to Glasgow, where Jerry was brought up in poverty. His childhood experiences of Glasgow's slums informed his later work, and led to his membership of the Labour Party which he joined at age 16, and only left when in his nineties in his disgust at the Second Gulf War. In his interview with Max Blythe, Morris notes that he once had rickets and signs of the disease were evident into adulthood, and stated that rickets were an indicator of poverty.