John Fairfax (1623–1700) was an English ejected minister.
Fairfax was the second son of Benjamin Fairfax (1592–1675), ejected from Rumburgh, Suffolk, who married Sarah, daughter of Roger and Joane Galliard, of Ashwellthorpe, Norfolk, was born in 1623. Theophilus Brabourne, the sabbatarian, was his uncle by marriage. The Suffolk Fairfaxes are a branch of the ancient Fairfax family of Walton and Gilling, Yorkshire.
Fairfax dated his religious impressions from an incident which occurred in his eleventh year: ‘the (supposed) sudden death of his sister in the cradle.’ He was admitted at Corpus Christi College, Cambridge, in 1640. After graduating BA he was appointed a Fellow by the Earl of Manchester on 10 January 1645 (admitted 14 January) in the place of Thomas Briggs, ejected. He had qualified by subscribing the covenant, and undergoing an examination by the Westminster Assembly. He graduated M.A. in 1647.
From his fellowship he was ejected in 1650 or 1651, on refusing to take the engagement of 1649, promising fidelity to the Commonwealth, 'without a king or house of lords.’
He then obtained the rectory of Barking-cum-Needham, Suffolk, and held it until the 1662 Act of Uniformity. Fairfax continued to reside in his own house at Barking, and used all opportunities of preaching. He was supported by Dame Brook (died 22 July 1683, aged 82), widow of Sir Robert Brook of Cockfield Hall, near Yoxford, Suffolk, who patronised nonconformists. He was also aided by his neighbour, John Meadows, an ejected minister of good property, who later married his niece.