The Falcons went an NFC-best 13-3 during the 2010 regular season before losing 48-21 at home to eventual NFC champion Green Bay in the divisional round of the playoffs.
Atlanta has posted three consecutive winning seasons under Smith, a franchise first, and has a 33-17 record during the span.
Financial terms of the deal were not announced.
(Reporting by Gene Cherry in Salvo, North Carolina. Editing by Steve Ginsburg)