Philip Jacobson was born on 10 September 1938 to Sydney, later Baron, Jacobson, and his wife. His father was political editor of the "Daily Mirror" and later editor of the "Daily Herald" and "The Sun". Jacobson was brought up in Stanmore, Middlesex, and educated in Dorset and at schools elsewhere. He did his national service in a tank regiment that was stationed in Malaya during the emergency. Afterwards he took a degree in politics at the London School of Economics.