Similarly to his friend Poirot, details of Hastings's life before 1916 are not revealed, though the reader is able to pinpoint Hastings's approximate birth year as 1886 from the first chapter of "The Mysterious Affair at Styles", as he mentions that John Cavendish was 'a good fifteen years senior' though hardly looking 'his forty-five years'. This makes Hastings thirty years old at the start of the novel. It is also mentioned later on that he was employed at Lloyd's prior to the war. Neither his first name nor his rank is mentioned in this novel. Elsewhere he states that he attended Eton College.