Israel Williams was a Massachusetts Loyalist. He was the son of Rev. William Williams of Hatfield, Massachusetts, who graduated from Harvard College in 1683. Israel Williams graduated from the same college in 1727. After graduation he returned to Hatfield and began accumulating wealth through trading, farming, and land speculation. For several decades he represented Hatfield in the Massachusetts legislature, and served on the executive council from 1761-1767. In 1748, he was appointed the Colonel of the Hampshire County militia and in this capacity was responsible for the defense of western Massachusetts during the French and Indian Wars.
During his long public career he served as a justice of the peace, judge of the court of common pleas for Hampshire County, a judge of the probate court, and was the founder of Williams College. In 1774, he was appointed a Massachusetts mandamus councillor but did not take the oath of office.
As the American Revolution approached, he was forced to withdraw from public life. During the early years of the Revolution, he was considered one of the leading Loyalists in western Massachusetts. As a result, in 1777 he was imprisoned in Northampton for several months and later confined to his house and deprived of his citizenship until 1780. On one occasion when he was an old man, he was taken from his home by a mob and carried several miles, then placed in a room with a fire but with the doors and chimney closed. He was confined there for several hours and on being released was forced to sign a document dictated by the mob. In 1786, he petitioned the British government for compensation for his sufferings and loss of income. At that time he was living quietly in Hatfield, and died there in 1788 at the age of seventy-nine.