Loder worked as a clerk in the Foreign Office from 1919 to 1922 and then for two years at the League of Nations in Geneva. On 3 June 1920, he married Margaret "Peggy" Tennant, the daughter of prominent Liberal politician and businessman, Sir Charles Tennant, 1st Baronet. Together they had four children: three sons, Christopher, David and Robert, and a daughter, Henrietta. Indulging in his interest in Egyptology, Loder wrote his first book: "The Truth about Mesopotamia, Syria and Palestine." (1923).