Prior to the encroachment of white settlers in present day Sevier County in the mid-18th century, the area had been inhabited for as many as 20,000 years by nomadic and semi-nomadic Native Americans. In the mid-16th century, Spanish expeditions led by Hernando de Soto (1540) and Juan Pardo (1567) passed through what is now Sevier County, reporting that the region was part of the domain of Chiaha, a minor Muskogean chiefdom centered around a village located on a now-submerged island just upsteam from modern Douglas Dam. By the late 17th-century, however, the Cherokee— whose ancestors were living in the mountains at the time of the Spaniards' visit— had become the dominant tribe in the region. Although they used the region primarily as hunting grounds, the Cherokee vehemently fought white settlement in their territory, frequently leading raids on households in the area, even through the signing of various peace treaties, alternating short periods of peace with violent hostility, until forcibly marched from their territory by the U.S. government on the infamous "Trail of Tears".
Sevier County as it is known today was formed on September 18, 1794 from part of neighboring Jefferson County, and has retained its original boundaries ever since. The county takes its name from John Sevier, governor of the failed state of Franklin and first governor of Tennessee, who played a prominent role during the tumultuous early years of settlement in the region. Since its establishment in 1795, the county seat has been situated at Sevierville (also named for Sevier), the eighth-oldest city in Tennessee.