Grimes was the son of Sir Thomas Grimes and his wife Margaret More, daughter of Sir George More of Loseley Park and was baptised on 10 February 1605. In 1628, he was elected Member of Parliament for Haslemere and sat until 1629 when King Charles decided to rule without parliament for eleven years. Grimes was knighted at Theobalds on 9 December 1628. He supported the King in the civil war, describing himself as having " for a long time wayted on His Majesty' s person as his sworne servant." 
Grimes died at the age of about 52 and was buried on 15 October 1657.
Grimes married Alice Lovell, daughter of Charles Lovell, of West Harling, Norfolk.
- William Harnett Blanch. Ye parish of Camerwell : a brief account of the parish of Camberwell : its history and antiquities
- Willis, Browne (1750). Notitia Parliamentaria, Part II: A Series or Lists of the Representatives in the several Parliaments held from the Reformation 1541, to the Restoration 1660 ... London. pp. 229–239.
- Knights of England
|Parliament of England|
|Member of Parliament for Haslemere
With: Sir Thomas Canon
Parliament suspended until 1640