Fanshawe was the second son of Thomas Fanshawe and first son by his second wife Joan Smythe, daughter of Customer Smythe and was baptised on 15 September 1580. His father was Queen's Remembrancer of the Exchequer. He was educated at Queens' College, Cambridge and admitted at the Inner Temple in 1595. He was an auditor for the Duchy of Lancaster. In 1601, he inherited the estate of Jenkins and Barking Manor, Essex, on the death of his father.
Also in 1601 Fanshawe was elected Member of Parliament for Bedford. He was elected MP for Lancaster in 1604. In 1606 became a barrister. He was re-elected MP for Lancaster in 1614 and 1621. He was knighted by King James in 1624. He was reelected MP for Lancaster in 1624, 1625, 1626 and 1628 and sat until 1629 when King Charles decided to rule without parliament for eleven years.
- Sybil M. Jack, ‘Fanshawe, Sir Thomas (1580–1631)’, Oxford Dictionary of National Biography, Oxford University Press, Sept 2004; online edn, Jan 2008, accessed 29 June 2010
- "Fanshawe, Thomas (FNSW589T)". A Cambridge Alumni Database. University of Cambridge.
- "History of Parliament". Retrieved 2011-10-10.
|Parliament of England|
|Member of Parliament for Bedford
With: Humphrey Winch
Sir Humphrey Winch
Sir Jerome Bowes
Sir Carew Reynell
|Member of Parliament for Lancaster
With: Sir Thomas Hesketh 1604–1605
Sir Thomas Howard 1605–1611
William Fanshawe 1614
Sir Humphrey May 1621–1624
John Selden 1624
Sir Humphrey May 1625
Thomas Jermyn 1626
Francis Bindlosse 1628–1629
Parliament suspended until 1640