A well-established minor gentry family of Warwickshire and Leicestershire, the Purefoys first settled at Caldecote, a few miles north of Nuneaton, in 1548. A junior member of this branch, Michael, sat for Nottingham in 1621. Purefoy was educated at Emmanuel College, Cambridge, a well-known training ground for radical Protestants, and around 1611 visited Geneva, where he allegedly first acquired a taste for republicanism. His father died in 1613, and two years later he inherited from his grandfather a small estate consisting principally of Caldecote and another local manor. Although the family had secured a £1,000 dowry when he married in 1609, his property was at first heavily encumbered with jointures and annuities.
Purefoy’s participation in local government was initially limited to the area near his home. In 1617 a William Purefoy was appointed muster-master of Coventry. Although it is possible that this was a namesake, Purefoy was certainly consulted in 1635 about Coventry’s militia arrangements.
In 1628 Purefoy emerged victorious from the disputed parliamentary elections at Coventry. On 1 Mar. the newsletter writer Joseph Mead attributed his success to his status as a Loan refuser, but this interpretation is questionable. Purefoy stood on a joint ticket with Richard Greene, who is not known to have opposed the Loan, and the election is more readily explicable in terms of Coventry’s internal politics. The defeated candidates, Isaac Walden and Thomas Potter, represented the unpopular ruling clique within the corporation, and it appears that Purefoy was recruited by a rival faction on the Mayor’s Council to help provide a focus for opposition. Technically Purefoy was ineligible to stand, being neither a freeman nor a resident of Coventry, but after much hesitation the Commons decided on 9 Apr. that his margin of victory at the polls was sufficient in itself for him to serve in the House. After this controversial introduction, he left no further trace on the records of the 1628 session. However, when Parliament resumed in the New Year he was named to committees to consider several trade-related petitions, and to scrutinize the bills concerned with the charter of the Somers Islands Company and corrupt ecclesiastical presentations (9 and 23 February).
Purefoy initially refused to compound for knighthood in 1630, stating that ‘he believeth himself not legally liable to be fined’. Nevertheless, he was pricked as sheriff of Warwickshire that year, and added to the county’s bench in 1632. A close political associate of Robert Greville*, 2nd Lord Brooke, who provided him with seats at Warwick in both the Short and Long Parliaments, he fought against the king during the Civil War, and signed his death warrant in January 1649.