He was called to the bar at Middle Temple in 1682, and was Town Clerk of Bodmin from 1692.
In 1695 he was elected to Parliament as Member for Bodmin, and retained the seat unopposed until his death.
Some sources erroneously state that the banker Sir John Houblon was elected three times as MP for Bodmin, apparently confusing him with Hoblyn.
He was married to Jane Symons in 1682 at Christ Church Greyfriars Newgate, London.
He also left property to his nephew Edward, which included The Barton of Colquite, the manor of Colquite and its mills and lands in St Mabyn, Egloshayle and Bodmin (except Pitt in St Mabyn).