Holland was just a boy when his father conspired against Henry IV and was attainted and executed. Nevertheless, he was given a chance to serve Henry V in the 1415 campaign in France, where he distinguished himself at Agincourt.
The next year Holland was restored in blood and to his father's earldom of Huntingdon, and was made a Knight of the Garter. (His older brother Richard had died in 1400.)
Over the next five years he held various important commands with the English forces in France, until he was captured by the French in 1421. He spent four years in captivity, not being released until 1425.
In 1435 he was appointed admiral of England, Ireland, and Aquitaine, and 1439 he was made the king's lieutenant in Aquitaine, and later governor of Aquitaine.
Holland recovered his father's dukedom of Exeter in 1439, and was given precedence just below the Duke of York. He was succeeded as duke by his son Henry.