In 1603, at the English coronation of King James I, Clifton was made a Knight of the Bath. He became a Justice of the Peace for Nottinghamshire in 1609, remaining until 1646. In 1611 he was third on the list of creations for the new order of baronet. He was active in local Nottinghamshire and national politics in both the reign of James I and Charles I. He was High Sheriff of Nottinghamshire in 1610 and High Steward of East Retford from 1616 to 1647. During the reign of King James he was elected Member of Parliament for Nottinghamshire in 1614, 1621, 1624 and 1625. He was County Treasurer from 1625 to 1626, and Deputy Lieutenant from 1626 to 1642. In 1626, he was elected MP for Nottingham and in 1628, he was re-elected MP for Nottinghamshire in 1628. He sat until 1629 when King Charles decided to rule without parliament for eleven years.
In November 1640, Clifton was elected MP for East Retford in the Long Parliament. He took up arms in the King's cause in the Civil War. He was a Commissioner for the King at Newark and Oxford, and a Commissioner of Array for Lincolnshire and Nottinghamshire in 1642. When King Charles called for members of the Long Parliament loyal to him to meet in session Oxford Clifton did so and was disabled from sitting in parliament at Westminster. With the defeat of the Royalist cause in 1646 and the capture of the King, Clifton lost his political influence both nationally and locally. He was declared a "delinquent" and fined £7,625 . By the time sequestration of his estates was ended in 1650 he had paid off about half of the money. He was not active in politics again until after the restoration of the monarchy in 1660. After the Restoration he regained his influence in Nottinghamshire and, from 1660, served Justice of the Peace for Nottinghamshire, High Steward of East Retford and Deputy Lieutenant. He was re-elected MP for Nottinghamshire in 1661 for the Cavalier Parliament. He held all these positions until his death, aged 78, in 1666.
Family
Clifton was born to his mother Lady Winifred Thorold three months after the death of his father Sir George Clifton, in 1587. The next year, with the death of his grandfather, Sir Gervase Clifton, he inherited the Clifton estates in Nottinghamshire. His guardians were his uncle, William Thorold, and Lord Burghley, although his early care fell to his maternal grandmother Lady Anne Thorold. Later he was educated at St. John's College, Cambridge, and at the Inner Temple. Clifton was married seven times and had thirteen children. He married Lady Penelope Rich, daughter of Robert Rich, 1st Earl of Warwick, and Lady Penelope Devereux. This marriage produced one son:
He married Mary Egioke, daughter of John Egioke of Egioke Manor, Inkberrow, Worcestershire, by his wife Anne, daughter of Nicholas Huband, of Ipsley, Warwickshire. He married Isobel Meek. He married Anne South, daughter of Sir Francis South of Kelstern, Lincolnshire. He married Jane Eyre, daughter of Anthony Eyre of Laughton-en-le-Morthen, Nottinghamshire, and Rampton, Nottinghamshire. This marriage produced four children:
