Philip Yorke was the only son of Philip Yorke (d.1721), an attorney of Dover, and his wife Elizabeth, daughter of Richard Gibbon of Dover. He was born in Dover on 1 December 1690, and was educated at a private school at Bethnal Green, whence he passed directly into the offices of a London solicitor and then to the Middle Temple, where he was admitted on 29 November 1708 and called to the bar on 27 May 1715. He subsequently moved to Lincoln's Inn where he held various posts including treasurer and master of the library.

He made many friends and secured the patronage of Lord Macclesfield, successfully standing as MP first for Lewes and then for Seaford, which he continued to represent until his elevation to the peerage. He rose rapidly in the legal profession, and was sworn in as solicitor-general in March 1719 and knighted shortly thereafter; in 1723 he was made solicitor-general, in which office he continued on the accession of George II. In 1732 he was appointed chief justice at a salary of £4,000, double that of his predecessor; he was sworn of the privy council on 1 November of that year and two days later created Baron Hardwicke of Hardwicke in Gloucestershire, where he already had a seat. He entered the House of Lords in January of the following year. He served as Lord Chancellor from 1737 until his resignation in 1756 and was created Earl of Hardwicke and Viscount Royston in 1754.

Regarded by his contemporaries as the quintessence of 'Whiggism', he was the eminence grise of successive administrations, particularly as the confidant and mentor of the young Henry Pelham, Duke of Newcastle. He was considered one of the handsomest men of his day, with a musical voice and eloquent and stately manner of public speaking; he was also a prolific author of legal text and correspondence and many of his speeches were published contemporaneously. His offices, though held to be moderate and just in the main, were not without controversy as he occasionally vacillated in his support for ministers such as Pitt and Bute, and Horace Walpole was his implacable opponent.

He married on 16 May 1719, Margaret, daughter of Charles Cocks of Worcester, with whom he had two daughters and five sons. He amassed a considerable fortune and in 1740 purchased Wimpole Hall from Edward Harley, 2nd Earl of Oxford (1689-1741), where he employed Henry Flitcroft to reface the central block of the house and also undertook much internal decoration. He died at his house in Grosvenor Square on 6 March 1764 and was succeeded by his eldest son, Philip.