Henry was the second son of Henry or Robert Fanshawe, who died in 1523. The Fanshawe family originated from Fanshawe Gate in Derbyshire. Henry was educated at Beauchief Abbey School and probably moved to London aged 16 or 17. He began his career as a sworn clerk in the Queen’s Remembrancer Office and an Under-Chamberlain of the Exchequer. He married twice, first Thomasine, daughter of William Hopkins, widow of Robert Steyns, in around 1554; she died in 1561/1562 having had no children. His second wife was Dorothy Stonard, with whom he had three children, all girls: Anne (1562–1584), Darraty (1565–1566) and Susanna (1567–1610). Henry’s, and ultimately the Fanshawe’s, ties to Barking and Dagenham came after he bought the manors of Jenkins, Fulkes, Gallance, Westbury, and Valence (before and up to 1657), to add to his property and land in London, Derbyshire and elsewhere in Essex.