John Pordage, the astrologer and mystic, eldest son of Samuel Pordage (d. 1626), grocer, by his wife Elizabeth Taylor, was born in the parish of St. Dionis Backchurch, London, and baptised on 21st April 1607. He was curate in charge of St. Laurence's Church in Reading, in 1644, the vicar being Thomas Gilbert (1613-1694). Pordage is later described as vicar, but erroneously. By 1647 (after 9th November 1646), he was rector of Bradfield, Berkshire, a living in the gift of Elias Ashmole, who thought highly of his astrological knowledge. Baxter, who describes him as chief of the 'Behmenists,' or English followers of Jacob Boehme, knew of him through a young man, probably Abiezer Coppe, who in 1649 was living under Pordage's roof in a "family communion," the members "aspiring after the highest spiritual state" through "visible communion with angels." Baxter thought they tried to carry too far "the perfection of a monastical life." Among themselves this family went by scripture names: Pordage was 'Father Abraham,' his wife was 'Deborah.'

John Pordage was charged before the committee for plundered ministers with heresies comprised in nine articles, accusing him of a sort of mystical pantheism. But on 27th March 1651, the committee acquitted him on all counts. On 18th September 1654, he was summoned to appear on 5th October before the county commissioners (known as 'expurgators') at the Bear Inn, Speenhamland, Berkshire. The nine articles were revived against him at the instance of John Tickel, a presbyterian divine from Abingdon, Berkshire. The inquiry was successively adjourned to 19th October, 2nd November, 22nd November and 30th November, fresh articles being from time to time brought forward against him, to the number of fifty-six, in addition to the original nine. Most of them dealt with unsubstantial matters of personal gossip. The accusation of intercourse with spirits was pressed (from 19th October) by Christopher Fowler. It was made a charge against him that he had sheltered Robert Everard and Thomas Tany. One of his maid-servants, while attesting some of the stories about spirits, bore witness to the purity and piety of the family life. By 30th November, Pordage was too ill to appear. The inquiry was adjourned to 7th December at the Bear Inn, Reading. On 8th December, the commissioners ejected him as "ignorant and very insufficient for the work of the ministry." He was to leave the rectory at Bradfield by 2nd February and clear out his barns by 25 March 1655.

At the Restoration, Pordage was reinstated. In 1663, he became acquainted with Jane Lead and assisted her in the study of Jacob Boehme. In August 1673 or 1674 (there is a doubt about the year), Pordage and Mrs. Lead "first agreed to wait together in prayer and pure dedication." Francis Lee, Jane Lead's son-in-law, speaks warmly of Pordage's devoutness and sincerity, maintaining that "his conversation was such as malice itself can hardly except against." He was not, however, a man of robust intellect. His insight into Boehme's writings was feeble and his theosophy was of the emotional order. In his will, he describes himself as 'doctor in physick.' It does not appear that he held the degree of MD, though it was assigned to him by others, and he was commonly called Dr. Pordage.

He died in 1681 and was buried in St. Andrew's, Holborn, on 11th December. His will, made on 28th November 1681 and proved 17th January 1682, was witnessed by Jane Lead. His first wife, Mary Lane of Tenbury, Worcestershire, was buried at Bradfield on 25th August 1668. His second wife was Elizabeth, widow of Thomas Faldo of London. His son, Samuel, became a well-known poet, but there were also other sons: John, William and Benjamin. His daughter, Elizabeth, was buried at Bradfield on 23rd December 1663. Other daughters were Mary, Sarah (married Mr. Stistead) and Abigail. His brother, Francis, who survived him, was rector of Stanford Dingley in Berkshire.