[1] He was born at Weybridge, the eldest son of Henry Gay Hewlett, of Shaw Hall, Addington, Kent.
From 1896 to 1901 he was Keeper of Lands, Revenues, Records and Enrolments, a government post as adviser on matters of medieval law.
Hewlett married Hilda Beatrice Herbert on 3 January 1888 in St Peter's Church, Vauxhall, where her father was the incumbent vicar.
The couple had two children, a daughter, Pia, and a son, Francis, but separated in 1914, partly due to Hilda's increasing interest in aviation.
[4] Hewlett also wrote six novels based on the Icelandic Family sagas, these include The Light Heart and Thorgils of Treadholt.