John Adams's law office in his Braintree home. He wrote the Massachusetts Constitution at his stand-up desk (pictured in the center of the room).

At the Convention's first session, the delegates appointed a drafting committee of 31. That committee delegated its duties to a subcommittee of John Adams, Sam Adams, and James Bowdoin. Because John Adams was the foremost American authority on the theory and practice of government, he authored the committee's draft. By late October 1779, Adams had completed his work. He then returned to his duties in Europe.

In the Massachusetts Constitution, Adams perfected the plan of government he had outlined in Thoughts on Government. He also included a Declaration of Rights to guarantee individual liberties.