He was appointed governor of Hammes jointly with his elder brother John Blount, 3rd Baron Mountjoy in 1476.[4]
When, in 1484, the Earl of Oxford and William, 2nd Viscount Beaumont, were imprisoned at Hammes, Blount was apparently persuaded to switch to the Lancastrian side. Blount, Oxford, and Beaumont fled to join Henry Tudor, (the future Henry VII of England who was then living in exile in France).Blount remained with the Lancastrian forces and landed with Henry Tudor's forces in 1485 at Milford Haven, where he was knighted.[3]