Colonel Josiah Quincy was born on April 1, 1710, in Braintree, Massachusetts. He was named after his grandfather, Rev. Josiah Flynt. After graduating from Harvard in 1728, he returned to Braintree. In 1735, he relocated to Boston and became involved in commerce and shipbuilding. He later returned to Braintree in 1748. Josiah Quincy was an American Patriot and supporter, corresponding with General George Washington regarding British troop movements and maintaining a friendship with Benjamin Franklin. He was also related to Abigail Adams, the wife of John Adams and the mother of John Quincy Adams.

Inheriting the land from his father, Edmund, Josiah constructed his mansion on a 200-acre (81 ha) farm known as the “Lower Farm,” which had been in the family since 1635. Completed in 1770, the house overlooked Quincy Bay and featured an unusual hipped monitor roof, considered the oldest surviving example of this roof style from the original colonies. It also boasted a Chinese fretwork balustrade and a classical portico. The attic included four small rooms for servants, one with a fireplace.

During the American Revolution, Quincy supported General George Washington by observing the British fleet in Boston Harbor from his attic windows. He made note of one event on a glass pane by scratching “October 10, 1775 Governor Gage saild for England with a fair wind.” This glass pane has been preserved and is on display in the front hall.

In 1895, the house and some adjacent properties were sold to Frank E. Hall of Boston. In 1937, Edward R. Hall facilitated the transfer of the Josiah Quincy House to the Society for the Preservation of New England Antiquities. Today, the house is owned by Historic New England, a nonprofit historical organization, and is open to the public only four Saturdays a year and by special appointment. It was designated a National Historic Landmark in 1997 for its architectural significance and its association with the Quincy family.