The son of a Cumberland mine owner, Miller was educated at Rugby School and Hertford College, Oxford, where he gained a double first, and was called to the bar in 1889, but never practised law.
[2] In 1903 he and his wife left England for Italy, and despite an effort by Ronald Burrows to recruit Miller as the first incumbent of the Chair of Modern Greek and Byzantine History, Language, and Literature at London University, he and his wife spent the rest of their lives abroad.
They lived in Rome (at Via Palestro 36) until 1923, when Miller found Benito Mussolini's rise to power distasteful, and they moved to Athens.
[3] Although his work displays a "romantic view of the Crusades and the Frankish expansion into the Eastern Mediterranean" typical of 19th-century Western trends on the subject,[4] and is considered "clearly outdated" given the research produced in recent decades, it has had a major influence and remains widely used to this day.
[5] Particularly the 1908 The Latins in the Levant has "remained for decades the standard English-language narrative account of the period",[3] and is "still the main reference for undergraduates in search of information on medieval Greece".