Maurice was born in the castle of Küstrin in Brandenburg shortly after his family was driven from Bohemia during the bloody conflict that became known as the Thirty Years War.
The fourth son of Frederick the Fifth, Elector of the Palatinate, and his wife Elizabeth (sister of Charles the First of England), Maurice was brought up in Berlin by his Brandenburg relatives until 1628, when at the age of seven, he rejoined his parents who had taken refuge with Frederick Henry, Prince of Orange, in the Netherlands.
Aged 16, Maurice took up a military career, serving in the Dutch army under the Prince of Orange. He was commended for his courage at the siege of Breda in 1637. Three years later, he served in the Swedish army under General Banier.
In August 1642, Maurice accompanied his elder brother, Prince Rupert, to England to fight for their Uncle Charles against Parliament. While Rupert was given overall command of the Royalist cavalry, Maurice was commissioned colonel of a regiment of cavaliers and fought at powick Bridge, Edgehill and Brentford.
In March 1643, Maurice was given his first independent command when he led 2,000 troops and harassed Sir William Waller on the Welsh border. Maurice skirmished and manoeuvred skilfully, winning the battle of Ripple Field in April – the first time that Waller had been defeated.
Maurice next commanded the cavalry in the Marquis of Hertford's western army, which joined forces with Sir Ralph Hopton's victorious Cornishmen in June 1643. Maurice had wanted command of the entire western army and was resentful towards Hertford. Hopton was dismayed to find that Maurice did little to prevent his unruly cavaliers from plundering civilians in Hopton's home county of Somerset. Despite occasional brawls between the Cornish foot and the Oxford horse, the western army marched against Sir William Waller's headquarters at Bath.
The Prince was wounded and briefly taken prisoner during a skirmish at Chewton Mendip on 12 June 1643. At the Battle of Lansdown in July 1643, his cavalry were driven back by Hesilrige's Lobsters and many fled the field. Although Lansdown was marginally a Royalist victory, the army suffered severe losses. Hopton himself was badly injured in an ammunition explosion the next day, leaving Maurice to command the withdrawal to Devizes, pursued by Waller's army, which had been reinforced from the Bristol garrison. While Hopton and the infantry defended Devizes, Maurice broke out with 300 cavalry and rode to Oxford for reinforcements, covering the 45 miles from Devizes to Oxford in a single night. He returned with Lord Wilmot and Sir John Byron at the head of 1,800 horse to inflict a grievous defeat on Waller at Roundway Down. Maurice then joined Prince Rupert at the storming of Bristol, where he took command of Hopton's Cornish infantry.
After the capture of Bristol, Lord Hertford was recalled to Oxford and Maurice was given command of the entire western army with orders to reduce remaining Parliamentarian strongholds in the south-west.
He marched to consolidate the Earl of Carnarvon's successful campaign in Dorset, during which Dorchester, Weymouth and Portland had surrendered on generous terms. However, Maurice did not honour the terms of surrender and once again allowed his men to plunder, prompting Carnarvon to resign his commission in protest and return to Oxford. Maurice then marched to take command at the siege of Exeter, which surrendered to him on 4 September. The following month, he captured Dartmouth in a surprise attack and seized forty Parliamentarian ships in the harbour, which made a considerable addition to the Royalist fleet. Maurice next marched to besiege Plymouth but fell sick with fever in mid-November 1643 and withdrew from the siege to recover.
King Charles sent the royal physician William Harvey to attend Maurice, and also attempted to arrange a marriage to a rich French heiress in the hope of gaining further funds for the Royalist cause. Despite his uncle's pleas, however, Maurice remained unmarried.
In 1644, Maurice returned to command Royalist forces in the south-west. In April, he became bogged down at the long and costly siege of Lyme in Dorset, which he was finally forced to abandon on 15 June at the approach of the Earl of Essex. Maurice rejoined King Charles and led the Royalist advance guard in the defeat of Essex at Lostwithiel in September 1644. He was also present at the second Battle of Newbury, where his cavalry were routed in Waller's flank attack. However, Maurice collaborated with Sir Jacob Astley to successfully supervise the evacuation of the Royalist army to Oxford after the battle.
When Prince Rupert was appointed commander of all the Royalist armies in November 1644, Maurice took his place as Lieutenant-General in Wales and the Marches, though he was not granted Rupert's former title President of Wales.
Maurice set up his headquarters at Worcester in mid-January 1645. He began re-organising the Royalist war effort in the region but in mid-February, the Parliamentarian threat to Chester forced him to march north. He gathered all available Royalist forces at Shrewsbury and outmanoeuvred Sir William Brereton to lift the siege of Chester on 20 February. Two days later, however, the depleted garrison at Shrewsbury was overwhelmed in a surprise dawn attack, and the city, which had been a major Royalist base since the beginning of the war, was taken. As well as energetic Parliamentarian military campaigning in his region, Maurice was hampered by the emergence of the Clubmen and by a shift in Welsh public opinion in favour of Parliament.
Maurice collaborated with Rupert in preparing for the campaign that culminated in the Battle of Naseby in June 1645, during which he fought on the Royalist right wing leading his regiment of horse and his own troop of lifeguards.
After the Royalist defeat, Maurice returned to Worcester with orders to prepare it as a contingency Royalist capital in case Oxford fell. But when Rupert was disgraced for surrendering Bristol in October 1645, Maurice defended him to the King and accompanied Rupert when he forced his way into the King's presence to gain a hearing at Newark.
The two princes remained loyal to the end. They surrendered at Oxford in June 1646 and were banished from England by order of Parliament.
Maurice returned to the Prince of Orange's army until the summer of 1648 when he joined Prince Rupert and the Prince of Wales (later Charles the Second) in a squadron of warships that had defected to the Royalists. In 1649, Maurice sailed with Rupert on his raids against Commonwealth shipping from a base at Kinsale in southern Ireland until their squadron was chased by Robert Blake from the Irish Sea to Lisbon and the Mediterranean.
When Blake drove the brothers from the Mediterranean, they sailed to West Africa, where Maurice raised his flag as Rupert's vice-admiral in a captured English ship, renamed The Defiance. With only four ships remaining, they crossed the Atlantic in 1652, to resume their privateering activities in the West Indies.
Maurice was lost at sea during a storm near the Virgin Islands in mid-September 1652. His loss deeply affected Rupert who for many years believed a persistent rumour that Maurice had survived the storm and had been captured by the Spaniards.