Harrington threw for 192 yards and the touchdown, completing 19 of 26 passes.
Warrick Dunn ran for 89 yards and one touchdown for the Falcons (3-6), who have now won two in a row. Dunn added three receptions for 51 yards.
Vinny Testaverde overcame an ankle injury to complete 13 of 28 passes for 153 yards as the Panthers (4-5), lost their third straight game.
Interpol investigating stolen passports on missing flight
Senate Democrats to pull all-nighter on climate change