The earliest known record relating to Greenough is of his marriage in 1734 to Martha Clarke, daughter of William and Sarah Clarke of Boston. Nine children resulted from this marriage over the course of the next 16 years; four of these were sons. On January 27 of the year of his marriage he purchased a house on the northwest side of North Street, between Mill Creek and Union Street, from John White and Nathaniel Roberts. On August 1, 1736, Greenough purchased the house and land of his father-in-law, William Clarke, on the south side of Portland Street. On October 28 he mortgaged to his mother his house on Ann Street (which appears to have been the house he had purchased on North Street), and at the same time he deeded to his brother Newman all his right and title in his father's estate at the North End. Greenough was only 24 at the time of his marriage, and he apparently became involved in real estate, by choice or by necessity, to a considerable degree. Greenough, in 1744, was a member of a militia company in Boston,[91] and three years later, in 1747, he was listed as third sergeant. He was a firm patriot, held a town office, and was a founder and deacon of the New Brick Church in Boston. Greenough had a substantial interest in the holdings of his late father-in-law. For example, on August 11, 1744, he and his wife deeded to a merchant named James Pitts the seawall, or new wharf, "before the Town of Boston in the front and rear lying to the northward of King Street Pier, North Wharf and flats of James Bowdoin," all of which was part of the estate of his deceased father-in-law that apparently had been inherited by his wife. In the following year, on November 1, 1745, he purchased a house and land on Portland Street from his widowed mother-in-law and then on March 31, 1746, he and his wife deeded the same house and land to a merchant named Stephen Hall. Numerous other negotiations of the same nature are on record. At some time between 1748 and 1750 Greenough's first wife, Martha, died, and in 1750 he married Sarah Stoddard. Three more children, all sons, resulted from this second marriage. His real estate negotiations continued full pace during the second marriage as during the first.[92] Greenough's second wife preceded him in death, and Greenough died in 1785 at the age of 75. His will, probated on August 23, 1785, had been made on May 21, 1782;[93] it contained some interesting bequests: