Financial terms and length of the deal were not disclosed.
Early last month, the Falcons signed coach Mike Smith to a contract extension through the 2014 season.
Atlanta owner Arthur Blank hired Dimitroff as GM on Jan. 13, 2008, a couple of weeks after the team ended a 4-12 season that included the imprisonment of quarterback Michael Vick and the sudden departure of first-year coach Bobby Petrino.
Ten days after he took the GM job, Dimitroff hired Smith. The Falcons drafted franchise quarterback Matt Ryan in April 2008 and since have reached the playoffs twice, won an NFC South title and achieved consecutive winning records for the first time in franchise history.