Armine was created a baronet on 28 November 1619 and succeeded to the estates of his father on 22 January 1622. He was elected Member of Parliament for Boston at least in 1624 and possibly in 1621 to replace Sir Thomas Cheek who sat for another seat. In 1625, he was elected MP for Grantham and in 1626 MP for Lincolnshire. He acted as assistant to the managers of the parliamentary impeachment of the Duke of Buckingham in 1626. In 1627, he refused to collect an arbitrary "loan" which the King had attempted to impose on Lincolnshire, and was imprisoned as a result. He was elected MP for Lincolnshire again in 1628 and sat until 1629 when King Charles decided to rule without parliament for eleven years. He was Sheriff of Lincolnshire in 1630 and Sheriff of Huntingdonshire in 1639. In 1641, Armine was elected MP for Grantham again in the Long Parliament. At the outbreak of the Civil War, he declared for Parliament, and was sent on Parliament's behalf to discuss terms with the King in 1643. He was one of the judges who was elected for the trial of the King in 1649, but refused to sit. He was elected a member of the Council of State in 1649, and was re-elected in 1650 and 1651. Armine died in 1651 at the age of 57 and was buried at Lavington, otherwise known as Lenton, Lincolnshire.
Family
Armine married firstly, on 14 December 1619, Elizabeth Hicks, daughter of Sir Michael Hicks of Beverstone Castle, Gloucestershire, and of Ruckholte, in Low Leyton, Essex. By her he had children William who succeeded to the baronetcy, Theophilus Armine|Theophilus who became a parliamentary colonel in the civil wars, and was killed at Pontefract Castle, Michael who succeeded his brother to the baronetcy, Elizabeth, who married Sir Thomas Style of Wateringbury and Anne, who married Sir Thomas Barnardiston of Great Cotes. Armine married secondly, on 28 August 1628, Mary Holcroft, widow of Thomas Holcroft of Vale Royal and daughter of Henry Talbot, son of the Earl of Shrewsbury. She was a philanthropist who founded three hospitals, and also took an active interest in missionaries among Native Americans in England's colonies. By her, Sir William had one further child Talbot Armine.
