Exeter was for a time Constable of the Tower of London, and afterwards the rack there came to be called "the Duke of Exeter's daughter". He was a commander at the great Lancastrian victories at Wakefield and St Albans.
He married Anne of York, a sister of Edward IV. After his brother-in-law took the throne, Exeter remained a loyal Lancastrian, and his estates were given to his wife, who subsequently had their marriage annulled.
He was a commander at the Battle of Towton. He fled to Scotland after that defeat, and then joined Queen Margaret in her exile in France. During the brief period of Henry VI's restoration he was able to regain many of his estates and posts.
At the Battle of Barnet Exeter commanded the Lancastrian left flank. He was knocked out and left for dead, but survived. Afterwards he was imprisoned, then "volunteered" to serve on Edward's 1475 expedition to France. On the return voyage he fell overboard and drowned. Some say he was in fact thrown overboard at the king's command.