Fazakerley was the son of Henry Fazakerley, came of an old Lancashire family which long resided at Fazakerley, a township near Liverpool. His own house was at Prescot, Lancashire. On 9 February 1714 he was admitted of the Inner Temple from the Middle Temple, but was called to the bar from the latter society.
At first he practised chiefly in chambers as an equity counsel, but as his practice grew he began to appear not only in the equity court, but in the courts of common law, mostly to argue questions connected with conveyancing and the transfer of real property. Occasionally his knowledge of constitutional law led him to be retained in state trials.
Among his cases was the trial of Richard Francklin, a Fleet Street bookseller, on 3 December 1731, for publishing in The Craftsman of 2 January the letter from The Hague said to have been written by Lord Bolingbroke. Fazakerley was retained along with Thomas Bootle for the defence, and, in the words of Lord Mansfield, ‘started every objection and laboured every point as if the fate of the empire had been at stake’.
In January 1732 he was chosen to succeed Daniel Pulteney as M.P. for Preston. He retained his seat for life, being returned at the head of the poll in the contested election of 1741. In August 1742 Fazakerley was appointed recorder of Preston, an office he also held until his death. His politics, however, prevented his attaining the honours of his profession; he never became K.C..
Fazakerley entered parliament as an adherent of the Tory party; he was a Jacobite of the cautious type. He was listened to with attention, and by a section of his party came to be regarded as a leader. In a debate on the convention with Spain, 9 March 1739, whereby peace was secured on payment by the Spanish government of a compensation to English traders, he declared that if Sir Robert Walpole ‘were determined to carry it by a majority, he would never again appear in the house till he perceived a change of measures’. He also distinguished himself in the debates in May 1751, on Lord Hardwicke's Regency Bill, especially by his resolute opposition to the marriage clause. There is a story that Walpole prevailed on Hardwicke, then Sir Philip Yorke, to quit the chief justiceship for the chancellorship, by the declaration: ‘If by one o'clock you do not accept my offer, Fazakerley by two becomes lord keeper of the great seal, and one of the staunchest whigs in all England!’. Another of his speeches which attracted attention was that delivered against the Jews' Naturalisation Bill, 7 May 1753.
Fazakerley died at his house in Grosvenor Street, London, in February 1767. His will was proved at London on 16 March following.
He married 10 October 1723 Ann Lutwyche, who survived him; they had a son and a daughter. The son died 30 June 1737. Elizabeth, the daughter, was married 23 December 1744, with a dowry of £16,000 to Granville, eldest surviving son of John Leveson-Gower, 1st Earl Gower, and died 19 May 1745.