Born in Maidstone, Kent in 1627, and having lost his father while a little boy, George Swinnock was brought up in the home of his uncle Robert Swinnock, sometime mayor of Maidstone, in an environment saturated in the Puritan tradition of prayer and family worship. After graduation from Cambridge he remained as chaplain at New College until his appointment as a Fellow of Balliol College, Oxford in 1648. Two years later he became Vicar of Rickmansworth, Hertfordshire where he served until 1660 when he was appointed Vicar of Great Kimble in Buckinghamshire.
Deprived of his living in the Great Ejection of 1662, for the next decade Swinnock served as chaplain in the family of Richard Hampden of Great Hampden in Buckinghamshire. Following the Declaration of Indulgence he returned, in 1672, to minister in his home town of Maidstone, where he died in November 1673.