Harrington was elevated to starting quarterback after the suspension of Vick for the 2007 NFL season. Harrington performed well in the preseason, but after going 0-2, Atlanta signed former Jacksonville starting quarterback Byron Leftwich as a possible replacement for Harrington. During the Week 3 Atlanta home opener against the division rival Carolina Panthers, Harrington completed 31-of-44 passes with two touchdowns and no interceptions for a 110.1 passer rating in a 27–20 loss. In Week 4, Harrington improved on his numbers with a 121.7 passer rating, completing 23-of-29 passes for two touchdowns with no interceptions, leading the Falcons to their first win of the 2007 season.