The medieval earldom created in 1088 was held to be inheritable through a female line of descent, and thus was held by members of several families. It was traditionally associated with possession of Warwick Castle. The heraldic device of the Earls of Warwick, the bear and ragged staff, is believed to derive from two legendary Earls, Arthal and Morvidus. Arthal is to mean "bear", while Morvidus was to have slain a giant "with a young ash tree torn up by the roots."
The family name of Beaumont was Latinised to de Bello Monte ("from the beautiful mountain"); the family was also known as de Newburgh, Latinised to de Novo Burgo ("from the new borough/town"). Henry changed his named to de Newburgh, after the Castle de Neubourg, his home in Normandy. 
The title passed through several generations of the Beaumont family until Thomas, the 6th earl, died in 1242 without a male heir. The earldom then went to his sister Margaret and her husbands and on her death to her cousin William Maudit.
When he died also without a male heir the title passed to his daughter Isabel and her husband William Beauchamp and thence her son William, who became 9th earl.
This precedence was disputed however and with Henry’s death in 1445, also without male heir, the dukedom was extinguished. The earldom went to his infant daughter, and on her death a few years later passed to Henry's sister Anne and her husband Richard Neville, who became 16th earl and was known to history as "Warwick the Kingmaker".
After Richard Neville’s death the title was created for his son-in-law, George Plantagenet, 1st Duke of Clarence, husband of Neville's eldest daughter Isabella Neville, on 25 March 1472. It then passed to Richard and Anne’s grandson Edward, son of George, Duke of Clarence, and with his death in 1499 the title became extinct.
The title was next conferred upon the powerful statesman and soldier John Dudley, 1st Viscount Lisle. He had already been created Viscount Lisle in right of his deceased mother, Elizabeth Grey, in 1543, and was made Earl of Warwick in the Peerage of England in 1547. In 1551 he was further honoured when he was created Duke of Northumberland. In January 1553 Parliament passed the earldom to his eldest son John, the second Earl. He died young in 1554, and having been attainted along with his father in August 1553, the title became extinct until it was revived in 1561 for his younger brother Ambrose, the third Earl. He served as Master-General of the Ordnance and Lord Lieutenant of Warwickshire. On his death in 1590 the earldom became extinct.
The title was re-created when Robert Rich, 3rd Baron Rich, was made Earl of Warwick in 1618. This was despite the fact that the Rich family were not in possession of Warwick Castle (this was in the hands of the Greville family; see the 1759 creation below). His second son the Hon. Henry Rich was created Baron Kensington in 1623 and Earl of Holland in 1624. Lord Warwick was succeeded by his eldest son, the second Earl. He represented Maldon in the House of Commons and served as Lord Lieutenant of Essex.
His eldest son, the third Earl, sat as Member of Parliament for Essex. He died without surviving male issue and was succeeded by his younger brother, the fourth Earl. He represented Sandwich and Essex in Parliament. On his death the line of the second Earl of Warwick failed and the titles were inherited by his first cousin Robert Rich, 2nd Earl Holland, who became the fifth Earl of Warwick as well. He was the son of the aforementioned Henry Rich, 1st Earl of Holland, younger son of the first Earl of Warwick (see the Earl of Holland for earlier history of this branch of the family). This line of the family failed on the early death of his grandson, the seventh Earl, in 1721. The late Earl was succeeded by his second cousin Edward Rich, the eighth Earl. He was the grandson of the Hon. Cope Rich, younger son of the first Earl of Holland. On his death in 1759 all the titles became extinct.
Lady Mary Rich, daughter of the first Earl of Holland, married Sir John Campbell, 5th Baronet, who was created Earl of Breadalbane and Holland in 1681. Also, Lady Elizabeth Rich, only daughter and heiress of the fifth Earl of Warwick and second Earl of Holland, married Francis Edwardes. Their son William Edwardes succeeded to parts of the Rich estates and was created Baron Kensington in the Peerage of Ireland in 1776
The title was again re-created when Francis Greville, 8th Baron Brooke was made Earl of Warwick in the Peerage of Great Britain. In 1746 he had been created Earl Brooke, of Warwick Castle, in the Peerage of Great Britain. The earldom of Warwick created in 1618 for a member of the Rich family became extinct in September 1759, and in November of the same year Lord Brooke was created Earl of Warwick, re-uniting the earldom and Warwick Castle for the first time in over a century. In 1767 the Earl petitioned the House of Lords for permission to use just the more prestigious title and style of "Earl of Warwick" only, with the precedence of 1746. Such permission was never granted but the Earls nevertheless ceased to use the Brooke earldom in style, and have always been known (except in the House of Lords) simply as The Earl of Warwick.
The Earl was succeeded by his eldest son, the second Earl. He represented Warwick in Parliament and served as a Lord of Trade and as Lord Lieutenant of Warwickshire. His eldest son from his second marriage, the third Earl, sat as Member of Parliament for Warwick and held minor office in the second administration of Sir Robert Peel. He was also Lord Lieutenant of Warwickshire. He was succeeded by his son, the fourth Earl. He represented Warwickshire South in the House of Commons. His eldest son, the fifth Earl, was Conservative Member of Parliament for Somerset East and served as Lord Lieutenant of Essex. As of 2007 the titles are held the latter's great-great-grandson, the eighth earl, who succeeded his father in 1996.
Another member of the Greville family was the Liberal politician Fulke Southwell Greville-Nugent, 1st Baron Greville. He was a descendant of the fifth Baron Brooke.
The heir apparent is the present holder's son Charles Fulke Chester Greville, Lord Brooke (b. 1982)