Weston's roots trace to 1757, when Norfield Parish was established as part of the town of Fairfield. Thirty years later, in 1787, the Connecticut General Assembly formally recognized Weston as its own incorporated town. Long before that, the land had already seen thousands of years of human use, with archaeological evidence of hunting activity dating back roughly 5,000 years.

Early Weston was an agricultural community, but the water power of the Aspetuck and Saugatuck Rivers soon fueled forges and foundries, turning the villages of Lyon's Plain and Valley Forge into small industrial centers. By 1830, Weston had grown into a town of roughly 3,000 people, home to foundries, a grist mill, an ax manufacturer, and four churches.

During the Revolutionary War, Weston found itself in the path of the conflict: in April 1777, as British troops under General Tryon marched toward Danbury to destroy a Continental Army supply depot, Weston mothers and children were said to have taken refuge in the rocky wilderness known as Devil's Den. Three decades later, on December 14, 1807, Weston witnessed one of the first scientifically documented meteorite falls in American history, an event significant enough that a fragment of it became the founding piece of Yale University's meteorite collection.