Dunn signed with the Falcons as a free agent in 2002 and spent six seasons with the team. During his time in Atlanta, Dunn gained 5,981 rushing yards – fourth-most in Falcons history – and 30 touchdowns while averaging 4.2 yards per carry.

He caught 204 passes during his career with the Falcons – second-most among running backs in franchise history – for 1,635 yards – third-most among Atlanta running backs – and six touchdowns. From 2004-06, Dunn had three consecutive 1,000-yard rushing seasons, including his lone Pro Bowl year with the Falcons in 2005.

Dunn became part of NFL history in 2006, when he and quarterback Michael Vick became the first running back-quarterback duo to rush for 1,000 yards, apiece. In 2009, Dunn became a limited partner of the Falcons.