William Kiffin (1616-1701) was born in London. His parents both died in the Great Plague of 1625 when he was nine. In his early life he showed 'a small talent' for business and soon became wealthy. He was able then to devote himself to the pastoral ministry and help those less well off than himself.
In 1638 Kiffin joined an independent congregation and was unpersuaded by Laud's policies and thought them unbiblical. How he became a particular baptist is unclear. One view is that it was through contact with Henry Jessey's church. What is clear is that he adopted adult baptism for Christians and a closed (strict) view of communion. His debates with John Bunyan, who was an open Baptist, helped to shape the open and closed boundaries of the Baptists. He was married to his wife, Hannah, for 44 years.
He was the pastor of a church in Devonshire Square, London and remained there for the rest of his life. In 1644 he was one of the signatories of the 1644 First London Confession of Faith. As well as being a pastor Kiffin was also involved in politics and often used his influence to help fellow Baptists. He was MP for Middlesex in 1656, and a master of the Leathersellers' Company. He was appointed Alderman of the Ward of Cheap in the City of London in 1687. Wilson describes him as 'an active but reluctant, participant in the political affairs of the day' (p 70).