Originally from Northumberland, the Herles had been settled in the south-west only since the days of Sir John’s synonymous father. Whereas the senior branch of the family had intermarried with the Prideaux family and established their seat at Prideaux near Luxulian in Cornwall, the junior line owed much of their landholdings in the county to the acquisition of part of the lands of the Champernownes of Ilfracombe and Tywardreath by the elder Sir John, who before the end of Henry IV’s reign was nevertheless of sufficient standing to represent Cornwall in the Commons. The young John himself made his first appearance in public life four years later, when he first attested the county elections. Before embarking on a career in local administration, he set out to fight in Henry V’s French wars. He was still abroad when in early April 1418 his father suddenly died.
Not long after Herle’s return from Parliament, the government recognized his prominence in the county by appointing him sheriff of Cornwall in January 1426, in succession to Sir William Talbot†. There appears to have been some delay in his assumption of the office, for although he was appointed in mid January, it was Talbot who sealed the parliamentary indenture for the shire elections held on 11 Feb. as sheriff, whereas Herle merely attested it.
In the late autumn of 1435 Herle’s health appears to have begun to fail, and he hurriedly settled his estates on feoffees, as well as concluding a sale of his manor of Tywardreath to his heir presumptive, Sir William Bonville*, a distant relative with whom he shared no more than a great-great-grandfather in the early 14th-century landowner Henry Champernowne†.
