English soldier and royal official, a Lancastrian leader in the Wars of the Roses (Roses, Wars of the). He helped to restore the deposed King Henry VI (1470) and later (1485) to secure the English throne for the last surviving male claimant from the house of Lancaster, Henry Tudor, Earl of Richmond, afterward King Henry VII.

He was the second son of John de Vere, 12th Earl of Oxford, who, with his eldest son, Aubrey, was executed (February 1462) under the Yorkist king Edward IV. Several years later, the younger John de Vere fled to France with the “kingmaker,” Richard Neville, Earl of Warwick. Returning with Warwick in a successful attempt to restore Henry VI (September-October 1470), he was made constable of England, supplanting John Tiptoft, Earl of Worcester, who had put de Vere's father and brother to death and was in turn executed by de Vere. After leading the Lancastrian vanguard in the Battle of Barnet, Hertfordshire (April 14, 1471), in which Warwick was killed and the Yorkists were victorious, de Vere was again exiled to France.

Once more returning to Britain, he captured the island of St. Michael's Mount, Cornwall (1473), but surrendered after a siege and was imprisoned. On escaping (August 1484), he joined Henry Tudor, who was preparing to invade Wales and then England from France. For his service as commander of the right wing in Henry's victory at Bosworth Field, Leicestershire (Aug. 22, 1485), de Vere was again restored to his title and estates and was made chamberlain and admiral of England. Subsequently, he fought in the victory of Henry VII's army at Stoke, Nottinghamshire (June 16, 1487), the last battle of the Wars of the Roses, and crushed the 7th Baron Audley's Cornish rebels at Blackheath, south of London (1497).