Sir John, the second son of Henry, Baron Norreys of Rycote, and his wife, Margery the daughter of John, Lord Williams, was probably born about 1547. This date agrees with the statement of his servant, Daniel Gyles, as given in the contemporary tract entitled 'A Memorable Service of Norreys in Ireland'. Lord Willoughby, who was born on 12th October 1555, stated less probably that Norreys was of the same age as himself'; while the epitaph on Norreys' monument in Yattendon Church suggests the impossible date 1529 as the year of his birth.

Norreys is said to have spent some time in youth at a university; but a soldier's life attracted him at a young age and he received his first military training in 1571, when he served as a volunteer under Admiral Coligny in the civil wars in France. In 1573, he joined, as captain of a company, the army of English volunteers that was enlisted by Walter Devereux, 1st Earl of Essex, in his attempt to colonize Ulster. In the tedious struggle with the native Irish and their Scottish allies, Norreys displayed much military skill. Almost the last incident in Essex's disastrous enterprise was the dispatch of Norreys, at the head of 1,150 men, from Carrick Fergus to the island of Rathlin, with directions to drive thence the Macdonnells who had taken refuge there. Norreys' little army was transported in three frigates, one of which had Francis Drake as commander. The islanders fled before him to the castle; but after four days' siege, between 22nd and 26th July 1575, Norreys affected an entrance and massacred the men, women and children within its walls. This criminal procedure was approved by the English Government, but the easy victory failed to stem Essex's misfortunes. A useless fort was erected on the island and Norreys evacuated it. Within three months, he and his troops were recalled to Dublin and the colonization of Ulster was abandoned for the time being. But Norreys had, by then, reached the conclusion, which in later years he often pressed upon his superiors, that "Ireland was not to be brought to obedience but by force," and that England could only depend on large permanent garrisons for the maintenance of her supremacy.

In July 1577, Norreys crossed to the Low Countries at the head of another army of English volunteers. Fighting on behalf of the States-General in the revolt against their Spanish rulers, Norreys found himself opposed to a far more serious enemy than any he had encountered hitherto; but he proved himself equal to the situation. On 1st August 1578, the Dutch army, with which he was serving, was attacked at Rymenant by the Spanish commander, Don John of Austria. The Dutch troops broke at the first onset of the Spanish. But Norreys, with three thousand English soldiers, stood his ground and, after a fierce engagement in which he had three horses killed under him, the Spaniards fell back, leaving a thousand dead upon the field. Through 1579, he co-operated in Flanders with the French army under Francois de la Noue. On 20th February 1580, Norreys displayed exceptional prowess in the relief of Steenwyk, which was besieged by the Spaniards under the Count von Rennenberg; and, in operations round Meppel, he proved himself a match for the Spanish general Verdugo. His fame in England rose rapidly and William Blandie bestowed extravagant eulogy on him in his 'Castle or Picture of Pollicy' of 1581.

Norreys remained in the Netherlands - chiefly in Friesia - until March 1584; but the war was pursued with less energy in the last two years. When he was again in England, it was reported at court that he was "not to return in haste". In July 1584, he was sent, for a second time, to Ireland and was conferred with the responsible office of Lord President of Munster. He, at once, made his way to his province, but the misery that he found prevailing there he had no means of checking and his soldiers deserted him in order to serve again in the Low Countries. In September 1584, Norreys accompanied the Lord Deputy Perrot on an expedition against his earlier opponents, the Scottish settlers in Ulster. With the Earl of Ormonde, he set about clearing the country of cattle, the Scots' chief means of support, and seized fifty thousand beasts around Glenconkein in Londonderry. No decisive results followed and Norreys returned to Munster to urge the home government to plant English settlers there. In the following Winter, the Ulster Scots grew more threatening than before and Norreys was summoned to Dublin by Perrot. He complained that the Lord Deputy would not permit him to go north but, as MP for County Cork, he attended the Parliament which Perrot opened on 26th April 1685 and distinguished himself by the forcible eloquence with which he supported measures to confirm the Queen's authority over the country.

Norreys' ambition was, however, directed to other fields. He had no wish, he admitted, "to be drowned in this forgetful corner" and the news that the Spaniards were besieging Antwerp, and likely to capture it from the Dutch, aroused all his enthusiasm in behalf of his former allies. He was anxious that Queen Elizabeth should directly intervene in the struggle of the Dutch protestants with Spain. Obtaining a commission by which his office as President of Munster was temporarily transferred to his brother, Thomas, he hurried to London in May 1585. On 10th August, a treaty was concluded between Elizabeth and the States-General, whereby four thousand foot soldiers and four hundred horse were to be placed at their disposal. On 12th August, Norreys was appointed to the command of this army and left England twelve days later. The Queen, when informing the States-General of his appointment, reminded them of his former achievements in their service. "We hold him dear," she added, "and he deserves also to be dear to you". Soon after his arrival in Holland, Norreys stormed with conspicuous gallantry a fort held by the Spaniards near Arnhem; but the Queen, who still preferred her old policy of vacillation, resented his activity and wrote to him, on 31st October, that he had neglected his instructions, "her meaning in the action which she had undertaken being to defend and not to offend." Nevertheless, Norreys repulsed Alexander of Parma, the Spanish leader, in another skirmish before Arnhem, on 15th November, and threatened Nymegen, which "he found not so flexible as he had hoped." But he was without adequate supplies of clothing, food or money, and soon found himself in a desperate plight. There was alarming mortality among his troops and his appeals for aid were disregarded at home. In December, the Earl of Leicester arrived with a new English army and, accepting the office of Governor of the Low Countries, he inaugurated the open alliance of England with the Dutch, which the Queen had been very reluctant to recognise.

In February 1586, Norreys left Utrecht to relieve Grave. The city was besieged by Alexander of Parma and formed almost the only barrier to the advance of the Spaniards into the northern provinces of Holland. Norreys was joined by native troops under the command of Count Hohenlohe. Three thousand men thus formed the attacking force. A desperate encounter followed on 15th April and Norreys received a pike-wound in the breast; but he succeeded in forcing the Spanish lines and provisioning the town. Leicester described the engagement as a great victory and knighted Norreys during a great feast he gave at Utrecht on St. George's Day. Owing, however, to the treachery of Count Hemart, the Governor of Grave, the Spaniards, immediately afterwards, were admitted within its walls. Leicester ordered Hemart to be shot. Norreys urged some milder measure, a course which Leicester warmly resented. Leicester informed Lord Burghley that Norreys was in love with Hemart's aunt and had allowed his private feelings to influence his conduct of affairs. Norreys' real motive was doubtless a desire to conciliate native sentiment.

Meanwhile, Leicester's inexperience as a military commander rendered the English auxiliaries almost helpless and their camp was torn by internal dissensions. Jealous of Norreys' superior skill, Leicester was readily drawn into an open quarrel with him and its continuance throughout the campaign of 1586 was largely responsible for the want of success. Leicester complained to Walsingham that Norreys habitually treated him with disrespect. Norreys "matched," he said, "the late Earl of Sussex," his old enemy at court. "He will so dissemble, so crouch and so cunningly carry his doings as no man living would imagine that there were half the malice or vindicative mind that doth plainly his deeds prove to be.....Since the loss of Grave he is as coy and as strange to give any counsel or any advice as if he were a mere stranger to us". Leicester surmised that Norreys aspired to his command. Could not Walsingham secure Norreys' recall? Was there no need of him in Ireland? Walsingham took seriously these childish grumblings, which formed the main topic of Leicester's despatches, and he appealed to Norreys to treat Leicester in more conciliatory fashion. The Queen, however, understood Norreys' worth and declined to recall him. She openly attributed Leicester's complaints to private envy and the Earl found it politic to change his tone. In the August, he wrote home that he had always loved Norreys and, at length, found him tractable. In the sight of other observers than Leicester, Norreys combined tact with his courage. Writing to Burghley, from Arnhem on 24th May, Thomas Doyley commended his valour and wisdom, "but above the rest, his especial patience in temporising, wherein he exceedeth most of his age".

Despite his uncongenial environment, Norreys did good service in May 1586 in driving the Spaniards from Nymegen and the Betwe. But when he was ordered to Utrecht, in August, to protect South Holland, Leicester foolishly excluded from his control the regiment of Sir William Stanley, who was in the neighbourhood of Deventer, and thus deprived the operations of the homogeneity which was essential to success. Immediately afterwards, he received, from home, a commission as Colonel-General of the Infantry, with powers to nominate all foot captains.

On 22nd September, Norreys took a prominent part, jointly with Stanley, in the skirmish near Zutphen in which Sir Philip Sidney was fatally wounded. On 6th October, Leicester wrote: "Norreys is a most valiant soldier surely, and all are now perfect good friends here". But before the end of the year Norreys was recalled to England, despite the protests of the States-General, from whom his many achievements in their service had won golden opinions. At court, the Queen, despite her previous attitude, treated him with some disdain as the enemy of Leicester, but, in the Autumn of 1587, he was recalled to Holland. Lord Willoughby, who succeeded Leicester in the command in November 1687, wisely admitted that Norreys was better fitted for the post; but he resented the presence of Norreys in a subordinate capacity on the scene of his former triumphs. Disputes readily arose between them. The Queen treated Norreys with so much consideration that Willoughby declared him to be "more happy than a Caesar" and "If I were sufficient," he argued, "Norreys were superfluous". This view finally prevailed and, at the beginning of 1588, Norreys was at home once more. In the April, he was created an MA at Oxford, on the occasion of Essex's incorporation in that degree. During the Summer, while the arrangements for the resistance of the Spanish Armada were in progress, Norreys was at Tilbury and acted as marshal of the camp under Leicester. He was also employed in inspecting the fortifications of Dover and in preparing Kent to meet invasion. But his active services were not required. After the final defeat of the Armada, he strongly recommended an invasion of Spain and offered to collect troops in Ireland. In the October, he was ordered to the Low Countries in a new capacity, as Ambassador to the States-General, to thank them for their aid in resisting the Armada, to consider with them the further prosecution of the war and to arrange the withdrawal of troops to take part in an expedition to Portugal. Willoughby, still the Commander-in-Chief in Holland, was directed to give Norreys all the assistance in his power; "but he is so sufficient," Willoughby wrote, "to debate in this cause as my counsels are but drops in the sea."

In April 1589, Norreys took command, along with Drake, of the great expedition despatched to destroy the shipping on the coasts of Spain and Portugal, and to place the pretender Antonio on the throne of Portugal. Twenty-three thousand men were embarked under the two commanders. The enterprise excited in England almost as much enthusiasm as the struggle with the armada in the preceding year. The dramatist, George Peele, gave expression to the confidence popularly placed in Norreys in 'A Farewell. Entituled to the famous and fortunate Generalls of our English Forces: Sir Iohn Norreys and Syr Frauncis Drake, Knights, and all theyr brave and resolute followers' (1589). Peele reminded the soldiers, "You follow noble Norreys, whose renown, won in the fertile fields of Belgia, spreads by the gates of Europe to the courts of Christian kings and heathen potentates". On 20th April, Norreys landed near Corunna, surprised and burnt the lower part of the town and beat off, in a smart encounter at Burgos, a Spanish force, eight thousand strong, under the Conde de Altemira. Putting to sea again, Norreys directed an attack on Lisbon; but the enemy declined a general engagement and the expedition returned to Plymouth on 2nd July, without having achieved any decisive result. In April 1591, Norreys left England with three thousand foot soldiers to aid in Henry IV of France's campaign in Brittany against the forces of the League. He landed at St. Malo on 5th May and joined the army of Prince Dombes, son of the Duc de Montpensier. On 24th May, the town of Guingamp surrendered, after a brief siege, to Norreys and Dombes, and Henry IV subsequently extolled Norreys' valour in a letter to Queen Elizabeth. On 11th June, he defeated a body of Spanish and French soldiers at Chateau Laudran. Shortly afterwards, six hundred of his men were transferred to Normandy, where the Earl of Essex was similarly engaged about Rouen in fighting with Henry IV's enemies. Thenceforth Norreys' campaign proved indecisive and, at the end of February 1592, he returned home.

In September 1593, Norreys again set foot in Brittany. In November, he and the Duc D'Aumont seized the great fortress of Crozon, which the enemy had built to protect Brest. The victory was well contested and Norreys was wounded. In February 1594, he had fourteen hundred well-trained men under his command who "wanted nothing but a good opportunity to serve upon the enemy". But there were dissensions in the camp between Norreys and his French colleagues and, in May 1594, to the regret of King Henry, he was finally recalled.

The next year, Norreys was summoned to Ireland, which he never quitted again alive. The Lord Deputy, Sir William Russell, had proved himself unable to resist the power of O'Neill, Earl of Tyrone, in Ulster and, after proclaiming him a traitor, had appealed, in April 1595, to the English Government to send him a military commander to exercise unusually wide powers. The Queen's advisers selected Norreys, who was still nominally Lord President of Munster. Norreys' military reputation stood so high that many believed that the native Irish would be reduced to impotency by the terror of his name. Norreys was under no such delusion. His health was bad and he knew, too, that his appointment was unpopular in many circles. With Sir William Russell, he had an old standing quarrel and he had many enemies in the Queen's councils. The Earl of Essex endeavoured to nominate his friends to the subordinate offices on Norreys' new staff, and Norreys' free expressions of resentment increased the antipathy with which Essex's friends at court regarded him.

Norreys arrived at Waterford on 4th May 1595 but, upon disembarking, was disabled by an attack of ague. After some delay, he arrived in Dublin and set out on his first campaign in the June. He made Newry his headquarters. Russell followed closely in his tracks, but Norreys had no desire for Russell's aid and declined all responsibility as long as Russell was with the army. In July, however, Russell returned to Dublin, asserting that he left Norreys to undertake the conquest of Ulster by whatever means he chose. But Norreys deemed the task impossible without reinforcements. Scarcely fifteen hundred men were at his disposal and, in letters to Burghley and Cecil, he charged Russell with secretly endeavouring to thwart him and with concealing the imperfections of his army from the home government. On the other hand, the Earl of Tyrone recognised in Norreys an opponent to be feared and was easily persuaded to forward to him a signed paper, which he called his submission. But the terms demanded a full acknowledgment of Tyrone's local supremacy and were, at once, rejected by Norreys, with the approval of the Queen's advisers.

Norreys, after making vain efforts to bring Tyrone to an open engagement, resolved to winter in Armagh. The place was easily occupied but, while engaged in fortifying a neighbouring pass between Newry and Armagh, on 4th September, Norreys was attacked by the Irish and was wounded in the arm and side. The home government thereupon suggested that Norreys should reopen negotiations. Norreys, impressed by the defects in his equipment, had already suggested that Tyrone should be granted a free pardon on condition that he renounced Spain and the Pope. If further hostilities were attempted, it was needful that all the English forces in Ireland should be concentrated in Ulster. Meanwhile a truce was arranged with Tyrone to last until 1st January 1596, and one month longer if the Lord Deputy desired it.

The next year, Norreys was instructed to renew negotiations for a peace and a hollow arrangement was patched up at Dundalk. Sir William Russell plainly recognised that Tyrone was only seeking to gain time until help came from Spain and complained, with some justice, that "the knaves" had overreached Norreys. But for the moment Ulster was free from disturbance and Norreys was ordered to proceed, with Sir Geoffrey Fenton, to Connaught in order to arrange terms with the Irish chieftains there. He censured the rigorous policy of the Governor, Sir Richard Bingham, who was sent to Dublin and detained. But his efforts at a pacification of the province proved futile. He remained there from June until the middle of December, when he returned to Newry; but, as soon as he left the borders of Connaught, the rebellion blazed out as fiercely as of old. Russell protested that Norreys' "course of pacification" was not to the advantage of the Queen's Government and the dissensions between them were openly discussed on both sides of St. George's Channel. Each represented, in his official dispatches, the state of affairs in a different light and Tyrone took every advantage of the division in the English ranks. On 22nd October 1596, Anthony Bacon, whose relations with Essex naturally made him a harsh critic of Norreys, informed his mother that "from Ireland there were cross advertisements from the Lord Deputy on the one side and Sir John Norreys on the other, the first, as a good trumpet, sounding continually the alarm against the enemy; the latter serving as a treble viol to invite to dance and be merry upon false hopes of a hollow peace," and that these opposite accounts made many fear rather the ruin than the reformation of the state upon that infallible ground "quod omne regnum divisum in se dissipabitur"'. In December 1596, Norreys, in letters to Sir Robert Cecil, begged for his recall. He complained that all he did had been misrepresented at Whitehall, his health was failing and the unjust treatment accorded to him was likely to "soon make an end of him".

Until April 1597, Norreys, who remained at Newry, continued his negotiations with Tyrone, in the absence, he complained, of any definite instructions from Dublin; but the chieftain had no intention of surrendering any of his pretensions and it was plain that diplomacy was powerless to remove the danger that sprang from his predominance. At length, the Queen's patience was exhausted. She recognised that the war must be resumed. The suggestion that both Russell and Norreys should be recalled was practically adopted. Although Burghley's confidence in Norreys was not wholly dissipated, Thomas, Lord Borough, was dispatched, in the May, to fill Russell's place as Lord Deputy and to take the command of the army. The new viceroy belonged to Essex's party at the English court and had been on bad terms with Norreys in Holland. Norreys, although not recalled, was effectually humiliated and he felt the degradation keenly. "He had," he declared, "lost more blood in Her Majesty's service than any he knew, of what quality soever.....yet was he trodden to the ground with bitter disgrace" owing to "a mistaken information" of his enemies. But he met Borough on his arrival in Dublin with much counterfeit kindness and no rupture took place between them. In the June following, he retired to Munster, where he still held the office of president. His health was precarious, no immediate danger threatened his province and he asked for temporary leave in order to recruit his strength. In his absence, the rebels might be easily kept in check, he said; and, he added, "I am not envious, though others shall reap the fruits of my travail - an ordinary fortune of mine." Before any reply was sent to his appeal he died, on 3rd July, in the arms of his brother, Thomas, at the latter's house in Mallow.

The immediate cause of Norreys' death was gangrene, due to unskilful treatment of his old wounds, but a settled melancholy aggravated his ailments; and it was generally believed that he died of a broken heart, owing to the Queen's disregard of his twenty-six years' service. His body was embalmed and he is reported to have been buried in the parish church at Yattendon in Berkshire, although there is no entry in the parish register. His father is said to have given him the neighbouring fortified manor house, but he had had little leisure time to spend there. A monument, with a long inscription which very incorrectly describes his services, still stands in the church and his helmet hangs above it. His effigy also appears alongside his siblings upon the great Norreys monument in Westminster Abbey. The Queen sent to his parents a stately letter of condolence.

Sir John was popularly regarded as one of the most skilful and successful military officers of the day, and his achievements in Holland and Brittany fully supported his reputation. But his failure in Ireland in later life proved him incapable as a diplomatist and prone to dissipate his energy in futile wrangling with colleagues whom it was his duty to conciliate.