Grenville was lord of the manors of Stowe, Kilkhampton in Cornwall and of Bideford in Devon. He was also a soldier, an armed merchant fleet owner, privateer, colonizer, and explorer. He took part in the early English attempts to settle the New World, and also participated in the fight against the Spanish Armada. His non-military offices included Member of Parliament for Cornwall, High Sheriff of County Cork in 1569–70 and Sheriff of Cornwall in 1576–77. He was the grandfather of Sir Bevil Grenville (1596–1643) of English Civil War fame, whose son was John Granville, 1st Earl of Bath (1628–1701).