Norwalk's story begins in 1640, when Roger Ludlow purchased the land from the local Norwalk people, and colonists from Hartford settled the area in 1649. The town was formally incorporated in 1651. During the Revolutionary War, Norwalk paid a heavy price for its loyalty to the American cause: in 1779, British and Loyalist forces under Major General William Tryon burned the settlement to the ground. It was from Norwalk's shores that Nathan Hale set out across Long Island Sound on the mission that led to his capture and execution as an American spy.

Norwalk rebuilt and grew through the 19th century into a thriving seaport and, eventually, an industrial center, with oyster farming so central to the local economy that the city earned the nickname "Oyster Town." The neighboring community of South Norwalk developed its own distinct identity, chartering as its own city in 1870, a rivalry that included a dispute over sharing water systems and lasted for decades. In 1913, Norwalk and South Norwalk formally consolidated into a single city.

The 1970s brought a turning point for the South Norwalk district. Under then-Mayor William Collins, the city launched a revitalization effort to preserve SoNo's historic architecture, an initiative that led directly to the founding of The Maritime Aquarium in 1988 and transformed the neighborhood into the arts and dining destination it remains today.