Founded in 1808 as Carlin's Settlement and named for Benjamin Franklin, Franklin became the parish seat in 1811 and the first incorporated town in 1820. Though early settlers included French, Acadian, German, Danish and Irish, the town's culture and architecture is heavily influenced by the unusually large numbers of English that chose to settle there after the Louisiana Purchase in 1803. Numerous large sugar plantations arose in the area, and with the development of steam boating, Franklin became an interior sugar port. By the 1830s, Bayou Teche was the main street of Acadiana, with one plantation after another.

The area's sugar cane planters were among the South's wealthiest agriculturists. This is reflected in the grand plantation homes and mansions they built in Franklin and the surrounding countryside. Most of these magnificent structures are still standing and well preserved, giving Franklin its unique architectural flavor.

Franklin's Historic District is listed in the National Register of Historic Places and boasts over 420 noteworthy structures. Many of the spectacular Greek Revival antebellum homes are along the live oak arcade on the East Main boulevard. East Main Street retains its distinctive turn-of-the-century iron street light standards, which have become a symbol of the picturesque town.

Though a small town, Franklin has produced more than its share of statesmen, including five governors of Louisiana, four United States senators, a Chief Justice and a Lieutenant Governor. Additionally, Franklin was the boyhood home of Jefferson Davis, president of the Confederacy. Theodore "Teddy" Roosevelt made an appearance in Franklin, and parts of the film Easy Rider (1969) were filmed on Main Street.

During the Civil War, the Battle of Irish Bend was fought near Franklin on April 14, 1863. Though eventually forced to retreat, the badly outnumbered Confederate forces cost the Union troops significant losses. Four hundred men were killed or wounded in the confrontation, which proved to be an important point in stopping the Union drive to invade Texas.