Kammala jumla mai zuwa: An yi masa baftisma a St Benet's a London, shi ɗan Robert Dormer ne, 1st Earl na Carnarvon da Lady Anna Sophia Herbert, 'yar Philip Herbert, 4th Earl na Pembroke. Dormer ya sami ilimi a Jami'ar Oxford, inda ya kammala karatun digiri na biyu a shekara ta 1648. A 1643, a kan mahaifinsa mutuwa a
Ya ci nasara a kan mahaifinsa kuma ya zama Babban Shugaban Avenor da kuma Mai Kula da Hawks na Sarki. Mahaifiyarsa ta rasu 'yan watanni da suka shige.