[2] After finishing his legal studies in 1627, Winthrop accompanied the ill-fated expedition of the Duke of Buckingham for the relief of the Protestants of La Rochelle in France, and then traveled to Italy, the Ottoman Empire, and the Netherlands, returning to England in 1629.

He then lived for a time in Massachusetts, where he devoted himself to the study of science and attempted to interest the settlers in the development of the colony's mineral resources.

His success as a physician prompted the then-separate New Haven Colony to invite him to their settlement with the promise of a free house.

With the assistance of William Fiennes, Robert Greville, and Edward Montagu, Winthrop obtained a charter for the colony in May of 1662.

[9][10] The Conquest of New Netherland and subsequent Second Anglo-Dutch War caused financial difficulty for both Winthrop and Connecticut.

He took a trip to England from 1661 to 1663, wherein he showcased New World plants and animals to Charles II and read papers for the Royal Society.

[11] Winthrop would contribute two papers to the society's Philosophical Transactions: "Some Natural Curiosities from New England" and "Description, Culture and Use of Maize".

[12] With the telescope Winthrop claimed to have sighted a fifth moon of Jupiter, the existence of which would be confirmed by Edward Emerson Barnard in 1892.

They had nine children, including:[14] Winthrop died in Boston on April 6, 1676, where he had gone to attend a meeting of the commissioners of the United Colonies of New England.