Catherine was co-heiress of her father Sir William Huddesfield of Shillingford St George in Devon, who was Attorney General for England and Wales to Kings Edward IV (1461–1483)[5] and Henry VII (1485–1509).

In 1577, he was awarded a small pension for his courageous and successful attack on the rebel Rory Oge O'More, whose forces had been menacing the castle.

He received his knighthood in Christ Church, Dublin on 24 February 1586, at the hands of his friend, Sir John Perrot, the recently appointed lord deputy.

[7] He was present when the new lord deputy, William Fitzwilliam, dealt with the mutineers from Sir John Norris' regiments in Dublin and was appointed to the council on 25 August 1590.

[10] Soon after he was elected Member of Parliament for Queenborough,[7] In 1598 he went to France for a short time as ambassador to the court of King Henry IV in the company of secretary Cecil.

[9][8] Carew was appointed President of Munster on 27 January 1600,[7] at the height of the Nine Years War and landed with Lord Mountjoy at Howth Head a month later.

In August, Carew had accepted a reinforcement of 3,000 troops from England, but in the following May was dismayed when Mountjoy took 1,000 from him to supplement the crown army in its northern campaign, at a time when the threat of a Spanish landing in the south was at its highest.

But Carew remained on and, although he failed to intercept Hugh Roe O'Donnell on the rebel's remarkable march southward to relieve the Spanish forces which had made landfall at Kinsale in the winter of 1601, he did great service before and after the Battle of Kinsale, as he raided castles in the surrounding region in order to remove the advantage the Spanish had expected upon their landing.

In the course of this campaign, his violence devastated the rebels and the peasantry, and his conduct of the siege of Dunboy castle, the last major engagement in Munster during the war, was ruthless.

According to Philip O'Sullivan Beare, a group of around three hundred Gaelic Irish, including men, women and child civilians, were killed by English soldiers under George Carew.

Carew proved unpopular with elements of the Old English élite in Ireland, particularly over his strong opposition to the privileges enjoyed by the municipal corporations under royal charter.

On the death of Elizabeth I, he was confronted unexpectedly with serious civil disorder, when several towns under his jurisdiction refused to proclaim the new King James I.

His severe attitude is explained by his personal interest in the matter since Lady Carew's life was said to have been threatened during the riots, and she had been forced to take refuge in Shandon Castle.

[11] Carew also received large sums from the treasury to pay the queen's debts to the goldsmith George Heriot, the mercer William Stone, Elias Tillier a linen draper, and the silkman Thomas Henshawe.

He gathered a large collection of materials relating to Irish history and pedigrees, which he left to his secretary, Sir Thomas Stafford (supposed to be his illegitimate son).

[7][16] He was buried in the Clopton Chantry Chapel (founded by Sir Hugh Clopton (c. 1440 – 1496), a Mercer and Lord Mayor of London) in the Church of the Holy Trinity, Stratford-upon-Avon,[15] where survives his "noble monument (on which) the Earl and his Countess are represented lying side by side, in their robes and coronets, under an arch adorned by their coats of arms, in the midst whereof is a fair marble table containing (a) large epitaph, which is given at length by Prince".