Humphrey Brooke, the son of a London gentleman, was educated at Merchant Taylors' School and St John's College, Oxford. He graduated with a bachelor's degree in medicine in 1646 and practised while living with the family of his wife-to-be Elizabeth Walwyn. His father-in-law William Walwyn (d. 1681), a medical practitioner, was one of the leaders of the Levellers, a group whose views Brooke shared. Broadly they believed in ridding parliament and the law of corruption. They also wanted religious tolerance and the widening of Parliamentary representation. As a political movement they came into being around 1644 but by 1650 had little influence after a number were shot and their leaders, including Walwyn, were imprisoned in the Tower.
Brooke had a long and distinguished medical career publishing his first work A Conservatory of Health the year he married, 1650. It was a written for the man in the street as a guide to good health. In 1665 he published Cautionary Tales for Preventing Sickness. He was made a Fellow of the Royal College of Physicians in 1674. He died a rich man in 1693.