The son of Robert Hopton of Witham, Somerset, he appears to have been educated at Lincoln College, Oxford, and to have served in the army of Frederick V, Elector Palatine, in the early campaigns of the Thirty Years' War. In 1624 he was lieutenant-colonel of a regiment raised in England to serve in Mansfeld's army. King Charles I, at his coronation, made Hopton a Knight of the Bath. In the political troubles which preceded the outbreak of the Civil War, Hopton, as member of parliament successively for Bath, Somerset and Wells, at first opposed the royal policy, but after Strafford's attainder (for which he voted) he gradually became an ardent supporter of Charles, and at the beginning of the conflict he was made lieutenant-general under the marquess of Hertford in the west.
His first achievement was to rally Cornwall to the royal cause; his next, to carry the war from there into Devon. In May 1643 he won the brilliant victory of Stratton, in June he overran Devon, and on July 5 he inflicted a severe defeat on Sir William Waller at the Battle of Lansdowne. At Lansdowne he was severely wounded by the explosion of a powder-wagon and soon afterwards he was besieged in Devizes by Waller; he defended himself until relieved by the victory of the Battle of Roundway Down on July 13. He was soon afterwards created Baron Hopton of Stratton. But his successes in the west were cut short by the defeat of Cheriton or Alresford in March 1644. After this he served in the western campaign under Charles' own command, and towards the end of the war, after Goring had left England, he succeeded to the command of the royal army. It was too late to stem the tide of the parliament?s victory, and Hopton, defeated in his last stand at Torrington on February 16 1646, surrendered to Thomas Fairfax.
Subsequently he accompanied the Prince of Wales in his attempts to prolong the war in the Scilly Isles and the Channel Islands. His downright loyalty was incompatible with the spirit of concession and compromise which prevailed in the prince's council from 1649 to 1650, and he withdrew from active participation in the cause of royalism. He died in exile at Bruges in September 1652. The peerage became extinct at his death. The king, Prince Charles, and the governing circle appreciated the merits of "their faithful lieutenant less than did his enemies Waller and Fairfax, the former of whom wrote, 'hostility itself cannot violate my friendship to your person,' while the latter spoke of him as 'One whom we honour and esteem above any other of your party.'"