Wildman was educated at the University of Cambridge, and during the English Civil War served for a short time under Sir Thomas Fairfax.
He became prominent, however, not as a soldier but as an agitator, being in 1647 one of the leaders of a section of the army which objected to all compromise with the king. In a pamphlet, Putney Projects, he attacked Oliver Cromwell; he was responsible for The Cast of the Army Stated, and he put the views of his associates before the council of the army at a meeting in Putney church in October 1647. The authorities looked upon him with suspicion, and in January 1648 he and John Lilburne were imprisoned, preparations, says Clarendon, being made "for his trial and towards his execution." However, he was released in the following August, and for a time he was associated with the party known as the Levellers, but he quickly severed his connexion with them and became an officer in the army.
He was a large buyer of the land forfeited by the royalists, and in 1654 he entered the House of Commons as member for Scarborough. In the following year he was arrested for conspiring against Cromwell, and after his release four months later he resumed plotting, intriguing with royalists and republicans alike for the overthrow of the existing regime. In 1659 he helped to seize Windsor Castle for the Long Parliament, and then in November 1661 he was again a prisoner on suspicion of participating in republican plots. For six years he was a captive, only regaining his freedom after the fall of Clarendon in October 1667.
In or before 1681 Wildman became prominent among those who wece discontented with the rule of Charles II, being especially intimate with Algernon Sydney. He was undoubtedly involved in the Rye House Plot, and under James II he was active in the interests of the Duke of Monmouth, but took no part in the rising of 1685. He found it advisable, however, to escape to Holland, and returned to England with the army of William of Orange in 1688. In 1689 he was a member of the convention parliament.
Wildman was postmaster-general from April 1689 to February 1691, when some ugly rumours about his conduct brought about his dismissal. Nevertheless, he was knighted by William III in 1692. Sir John, who was the author of many political pamphlets, left an only son, John, who died childless in 1710.
This entry was originally from the 1911 Encyclopedia Britannica.