When Colonel Ephraim Williams of the Massachusetts militia was killed at the Battle of Lake George in 1755, his will included a bequest to support and maintain a free school to be established in the town of West Hoosac, Massachusetts, provided that the town change its name to Williamstown. The will was unsigned and undated, and provided additional stipulations, such as the town remaining in Massachusetts rather than becoming part of New York as some residents wanted, before the bequest could be disbursed. This involved a delay of over 35 years until, in 1791, the Williamstown Free School opened. Not long after the school opened, the trustees petitioned the Massachusetts legislature to convert the free school to a tuition-based college. The legislature agreed and in 1793, Williams College was chartered.

In 1806 a student prayer meeting gave rise to the American Foreign Mission Movement. In August of that year five students met in the maple grove of Sloan's Meadow to pray. A thunderstorm drove them to the shelter of a haystack, and the fervor of the ensuing meeting inspired them to take the gospel abroad. The students went on to build the American Board of Commissioners for Foreign Missions, the first American organization to send missionaries overseas. The Haystack Monument near Mission Park on the Williams Campus commemorates the meeting.

By 1815, Williams had only two buildings and fifty-eight students, and was in serious financial trouble. On November 10, 1818, nine of the twelve Williams College trustees voted for a resolution stating that:

In February 1820, a petition to the Massachusetts legislature to this effect was defeated, and the college was not moved.

In 1821, Williams College President Zephaniah Swift Moore, who had accepted his position believing that the college would move east, abandoned Williams. He took fifteen students with him, and assumed the first Presidency of Amherst College. Story has it that Moore also took portions of the Williams College library. Though plausible, this account is unsubstantiated, and was declared false in 1995 by Williams College President Harry Payne. Moore died just two years later after founding Amherst, and was succeeded by Heman Humphrey, a trustee of Williams College.

Williams played Amherst College in the first intercollegiate baseball game in 1859 and continued on to pioneer many areas of academia and education. Williams' website has a list of "firsts"  and a more detailed history . Notable among these, Williams was the first American college or university to feature caps and gowns at graduation.

Presidents of Williams College

Ebenezer Fitch, 1793-1815

Zephaniah Swift Moore, 1815-1821

Edward Dorr Griffin, 1821-1836

Mark Hopkins, 1836-1872

Paul Ansel Chadbourne, 1872-1881

Franklin Carter, 1881-1901

John Haskell Hewitt, 1901-1902

Henry Hopkins, 1902-1908

Harry Augustus Garfield, 1908-1934

Tyler Dennett, 1934-1937

James Phinney Baxter, 1937-1961

John Edward Sawyer, 1961-1973

John Wesley Chandler, 1973-1985

Francis Christopher Oakley, 1985-1993

Harry C. Payne, 1994-1999

Carl W. Vogt, 1999-2000

Morton Owen Schapiro, 2000-present